diff --git a/diylc/diylc-core/src/main/java/org/diylc/common/IVariantProcessor.java b/diylc/diylc-core/src/main/java/org/diylc/common/IVariantProcessor.java
index 8dcd6cf0..bf5cf45f 100644
--- a/diylc/diylc-core/src/main/java/org/diylc/common/IVariantProcessor.java
+++ b/diylc/diylc-core/src/main/java/org/diylc/common/IVariantProcessor.java
@@ -43,6 +43,10 @@ public interface IVariantProcessor {
   void deleteVariant(ComponentType type, String variantName);
 
   void setDefaultVariant(ComponentType type, String variantName);
+
+  void setDefaultModel(ComponentType type, String[] model);
+
+  boolean isDefaultModel(ComponentType type, String[] model);
   
   int importVariants(String fileName) throws IOException;
   
diff --git a/diylc/diylc-core/src/main/java/org/diylc/presenter/Presenter.java b/diylc/diylc-core/src/main/java/org/diylc/presenter/Presenter.java
index cd8f97f0..fd792530 100644
--- a/diylc/diylc-core/src/main/java/org/diylc/presenter/Presenter.java
+++ b/diylc/diylc-core/src/main/java/org/diylc/presenter/Presenter.java
@@ -2868,17 +2868,21 @@ public class Presenter implements IPlugInPort {
       controlPointMap.clear();
     }
 
-    // try to find a default template if none is provided
-    if (componentType != null && template == null) {
-      String defaultTemplate = getDefaultVariant(componentType);
-      List<Template> templates = getVariantsFor(componentType);
-      if (templates != null && defaultTemplate != null)
-        for (Template t : templates) {
-          if (t.getName().equals(defaultTemplate)) {
-            template = t;
-            break;
+    // try to find a default model or template if none is provided
+    if (componentType != null && template == null && model == null) {
+      model = variantManager.getDefaultModel(componentType);
+      if (model == null) {
+        String defaultTemplate = getDefaultVariant(componentType);
+        List<Template> templates = getVariantsFor(componentType);
+        if (templates != null && defaultTemplate != null) {
+          for (Template t : templates) {
+            if (t.getName().equals(defaultTemplate)) {
+              template = t;
+              break;
+            }
           }
         }
+      }
     }
 
     try {
@@ -3064,28 +3068,19 @@ public class Presenter implements IPlugInPort {
     variantManager.deleteVariant(type, templateName);
   }
 
-  @SuppressWarnings("unchecked")
   @Override
   public void setDefaultVariant(ComponentType type, String templateName) {
-    LOG.debug(String.format("setTemplateDefault(%s, %s)", type, templateName));
-    Map<String, String> defaultTemplateMap =
-        (Map<String, String>) configManager.readObject(DEFAULT_TEMPLATES_KEY, null);
-    if (defaultTemplateMap == null)
-      defaultTemplateMap = new HashMap<String, String>();
+    variantManager.setDefaultVariant(type, templateName);
+  }
 
-    // try by class name and then by old category.type format
-    String key1 = type.getInstanceClass().getCanonicalName();
-    String key2 = type.getCategory() + "." + type.getName();
+  @Override
+  public void setDefaultModel(ComponentType type, String[] model) {
+    variantManager.setDefaultModel(type, model);
+  }
 
-    if (templateName.equals(defaultTemplateMap.get(key1)) || templateName.equals(defaultTemplateMap.get(key2))) {
-      defaultTemplateMap.remove(key1);
-      defaultTemplateMap.remove(key2);
-    } else {
-      // get rid of legacy key
-      defaultTemplateMap.remove(key2);
-      defaultTemplateMap.put(key1, templateName);
-    }
-    configManager.writeValue(DEFAULT_TEMPLATES_KEY, defaultTemplateMap);
+  @Override
+  public boolean isDefaultModel(ComponentType type, String[] model) {
+    return variantManager.isDefaultModel(type, model);
   }
 
   @Override
diff --git a/diylc/diylc-core/src/main/java/org/diylc/presenter/VariantManager.java b/diylc/diylc-core/src/main/java/org/diylc/presenter/VariantManager.java
index 97c5c0d0..4e8f48ab 100644
--- a/diylc/diylc-core/src/main/java/org/diylc/presenter/VariantManager.java
+++ b/diylc/diylc-core/src/main/java/org/diylc/presenter/VariantManager.java
@@ -23,6 +23,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.time.LocalDateTime;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
@@ -46,6 +47,9 @@ import org.diylc.serialization.ProjectFileManager;
 public class VariantManager {
 
   private static final String VARIANTS_FILE_NAME = "import-defaults/variants.xml";
+  // marks a default that names a datasheet model rather than a variant; older versions find no
+  // variant by that name and simply place the component without a default
+  private static final String DATASHEET_MODEL_PREFIX = "datasheet:";
 
   private static final Logger LOG = Logger.getLogger(VariantManager.class);
 
@@ -261,6 +265,67 @@ public class VariantManager {
     return defaultTemplateMap.get(key2);
   }
 
+  /**
+   * Makes the variant the default of its type, replacing whatever variant or model was the
+   * default before, or clears the default if the variant already is it.
+   */
+  @SuppressWarnings("unchecked")
+  public void setDefaultVariant(ComponentType type, String variantName) {
+    Map<String, String> defaultTemplateMap =
+        (Map<String, String>) configManager.readObject(IPlugInPort.DEFAULT_TEMPLATES_KEY, null);
+    if (defaultTemplateMap == null) {
+      defaultTemplateMap = new HashMap<String, String>();
+    }
+
+    // try by class name and then by old category.type format
+    String key1 = type.getInstanceClass().getCanonicalName();
+    String key2 = type.getCategory() + "." + type.getName();
+
+    if (variantName.equals(defaultTemplateMap.get(key1))
+        || variantName.equals(defaultTemplateMap.get(key2))) {
+      defaultTemplateMap.remove(key1);
+      defaultTemplateMap.remove(key2);
+      LOG.info(String.format("Cleared default of %s, was %s", type.getName(), variantName));
+    } else {
+      // get rid of legacy key
+      defaultTemplateMap.remove(key2);
+      defaultTemplateMap.put(key1, variantName);
+      LOG.info(String.format("Set default of %s to %s", type.getName(), variantName));
+    }
+    configManager.writeValue(IPlugInPort.DEFAULT_TEMPLATES_KEY, defaultTemplateMap);
+  }
+
+  /**
+   * Same as {@link #setDefaultVariant(ComponentType, String)} for a datasheet model, sharing the
+   * single default slot of the type.
+   */
+  public void setDefaultModel(ComponentType type, String[] model) {
+    setDefaultVariant(type, encodeModel(type, model));
+  }
+
+  public boolean isDefaultModel(ComponentType type, String[] model) {
+    return encodeModel(type, model).equals(getDefaultVariant(type));
+  }
+
+  /**
+   * @return the datasheet row pinned as the default of the type, or null when the default is a
+   *         variant, nothing is pinned, or the pinned model is no longer in the datasheet.
+   */
+  public String[] getDefaultModel(ComponentType type) {
+    String defaultVariant = getDefaultVariant(type);
+    List<String[]> datasheet = type.getDatasheet();
+    if (defaultVariant == null || !defaultVariant.startsWith(DATASHEET_MODEL_PREFIX)
+        || datasheet == null) {
+      return null;
+    }
+    for (String[] row : datasheet) {
+      if (defaultVariant.equals(encodeModel(type, row))) {
+        return row;
+      }
+    }
+    return null;
+  }
+
   @SuppressWarnings("unchecked")
   public void deleteVariant(ComponentType type, String templateName) {
     LOG.debug(String.format("deleteTemplate(%s, %s)", type, templateName));
@@ -294,4 +359,11 @@ public class VariantManager {
     }
     configManager.writeValue(IPlugInPort.TEMPLATES_KEY, templateMap);
   }
+
+  // a model is identified by its path through the datasheet submenus, the same columns the
+  // toolbox matches when a model is clicked
+  private String encodeModel(ComponentType type, String[] model) {
+    int depth = Math.min(type.getDatasheetCreationStepCount(), model.length);
+    return DATASHEET_MODEL_PREFIX + String.join("|", Arrays.copyOf(model, depth));
+  }
 }
diff --git a/diylc/diylc-core/src/main/resources/update.xml b/diylc/diylc-core/src/main/resources/update.xml
index 0d0493e3..7489db1d 100644
--- a/diylc/diylc-core/src/main/resources/update.xml
+++ b/diylc/diylc-core/src/main/resources/update.xml
@@ -549,6 +549,10 @@
 					<changeType>NEW_FEATURE</changeType>
 					<description>Added a datasheet to 'Enclosure' with Hammond 1590, 1550, 1441 and 1444 enclosures and the 125B size - more than 130 variations</description>
 				</org.diylc.appframework.update.Change>
+				<org.diylc.appframework.update.Change>
+					<changeType>NEW_FEATURE</changeType>
+					<description>Datasheet models in a component's drop-down menu now have the same pin as saved variants, so a model such as a 2N3904 can be made the default that is placed when the component is clicked; a component has one default, so pinning a model replaces a pinned variant and the other way round</description>
+				</org.diylc.appframework.update.Change>
 				<org.diylc.appframework.update.Change>
 					<changeType>IMPROVEMENT</changeType>
 					<description>Re-modeled factory variants of Resistor component type as datasheet in order to make them available to the AI; this will produce more accurate AI-driven edits</description>
diff --git a/diylc/diylc-core/src/test/java/org/diylc/presenter/VariantManagerTest.java b/diylc/diylc-core/src/test/java/org/diylc/presenter/VariantManagerTest.java
new file mode 100644
index 00000000..436c2d3f
--- /dev/null
+++ b/diylc/diylc-core/src/test/java/org/diylc/presenter/VariantManagerTest.java
@@ -0,0 +1,191 @@
+/*
+
+    DIY Layout Creator (DIYLC).
+    Copyright (c) 2009-2025 held jointly by the individual authors.
+
+    This file is part of DIYLC.
+
+    DIYLC is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    DIYLC is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DIYLC.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+package org.diylc.presenter;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.diylc.appframework.miscutils.IConfigListener;
+import org.diylc.appframework.miscutils.IConfigurationManager;
+import org.diylc.common.ComponentType;
+import org.diylc.common.IPlugInPort;
+import org.diylc.core.CreationMethod;
+import org.diylc.core.annotations.BomPolicy;
+import org.diylc.core.annotations.KeywordPolicy;
+import org.diylc.testcomponents.TwoPointTestComponent;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Covers the single default slot that variants and datasheet models share, see
+ * {@code docs/plans/default-datasheet-model.md}.
+ */
+public class VariantManagerTest {
+
+  private static final String[] NPN = new String[] {"BJT (NPN)", "2N3904", "BJT_EBC"};
+  private static final String[] PNP = new String[] {"BJT (PNP)", "2N3906", "BJT_EBC"};
+
+  private MapConfigurationManager configManager;
+  private ComponentType type;
+  private VariantManager manager;
+
+  @Before
+  public void setUp() {
+    configManager = new MapConfigurationManager();
+    type = createType(new ArrayList<String[]>(Arrays.asList(NPN, PNP)));
+    manager = new VariantManager(configManager, null);
+  }
+
+  @Test
+  public void pinningAModelMakesItTheDefault() {
+    manager.setDefaultModel(type, NPN);
+
+    assertTrue(manager.isDefaultModel(type, NPN));
+    assertFalse(manager.isDefaultModel(type, PNP));
+    assertArrayEquals(NPN, manager.getDefaultModel(type));
+    assertEquals("datasheet:BJT (NPN)|2N3904", manager.getDefaultVariant(type));
+  }
+
+  @Test
+  public void pinningTheDefaultModelAgainClearsIt() {
+    manager.setDefaultModel(type, NPN);
+    manager.setDefaultModel(type, NPN);
+
+    assertFalse(manager.isDefaultModel(type, NPN));
+    assertNull(manager.getDefaultModel(type));
+    assertNull(manager.getDefaultVariant(type));
+  }
+
+  @Test
+  public void pinningAnotherModelReplacesTheDefault() {
+    manager.setDefaultModel(type, NPN);
+    manager.setDefaultModel(type, PNP);
+
+    assertFalse(manager.isDefaultModel(type, NPN));
+    assertArrayEquals(PNP, manager.getDefaultModel(type));
+  }
+
+  @Test
+  public void modelAndVariantReplaceEachOther() {
+    manager.setDefaultVariant(type, "My variant");
+    manager.setDefaultModel(type, NPN);
+
+    assertArrayEquals(NPN, manager.getDefaultModel(type));
+
+    manager.setDefaultVariant(type, "My variant");
+
+    assertEquals("My variant", manager.getDefaultVariant(type));
+    assertNull(manager.getDefaultModel(type));
+  }
+
+  @Test
+  public void modelMissingFromTheDatasheetIsNoDefault() {
+    manager.setDefaultModel(type, NPN);
+    ComponentType reduced = createType(new ArrayList<String[]>(Arrays.<String[]>asList(PNP)));
+
+    assertNull(manager.getDefaultModel(reduced));
+  }
+
+  @Test
+  public void legacyKeyIsReadAndReplacedOnWrite() {
+    String legacyKey = type.getCategory() + "." + type.getName();
+    Map<String, String> defaults = new HashMap<String, String>();
+    defaults.put(legacyKey, "Old variant");
+    configManager.writeValue(IPlugInPort.DEFAULT_TEMPLATES_KEY, defaults);
+
+    assertEquals("Old variant", manager.getDefaultVariant(type));
+
+    manager.setDefaultModel(type, PNP);
+
+    @SuppressWarnings("unchecked")
+    Map<String, String> written = (Map<String, String>) configManager
+        .readObject(IPlugInPort.DEFAULT_TEMPLATES_KEY, null);
+    assertFalse(written.containsKey(legacyKey));
+    assertArrayEquals(PNP, manager.getDefaultModel(type));
+  }
+
+  private static ComponentType createType(List<String[]> datasheet) {
+    return new ComponentType("Test Transistor", "", CreationMethod.SINGLE_CLICK, "Test", "Q", "",
+        null, TwoPointTestComponent.class, 0, false, BomPolicy.SHOW_ALL_NAMES, false, null,
+        KeywordPolicy.NEVER_SHOW, null, false, datasheet, 2);
+  }
+
+  private static class MapConfigurationManager implements IConfigurationManager<Object> {
+
+    private final Map<String, Object> values = new HashMap<String, Object>();
+
+    @Override
+    public void addConfigListener(String key, IConfigListener listener) {}
+
+    @Override
+    public boolean readBoolean(String key, boolean defaultValue) {
+      return (Boolean) readObject(key, defaultValue);
+    }
+
+    @Override
+    public String readString(String key, String defaultValue) {
+      return (String) readObject(key, defaultValue);
+    }
+
+    @Override
+    public int readInt(String key, int defaultValue) {
+      return (Integer) readObject(key, defaultValue);
+    }
+
+    @Override
+    public float readFloat(String key, float defaultValue) {
+      return (Float) readObject(key, defaultValue);
+    }
+
+    @Override
+    public double readDouble(String key, double defaultValue) {
+      return (Double) readObject(key, defaultValue);
+    }
+
+    @Override
+    public Object readObject(String key, Object defaultValue) {
+      return values.containsKey(key) ? values.get(key) : defaultValue;
+    }
+
+    @Override
+    public void writeValue(String key, Object value) {
+      values.put(key, value);
+    }
+
+    @Override
+    public Object getSerializer() {
+      return null;
+    }
+
+    @Override
+    public void initialize(String appName) {}
+  }
+}
diff --git a/diylc/diylc-swing/src/main/java/org/diylc/swing/gui/ComponentPopupMenu.java b/diylc/diylc-swing/src/main/java/org/diylc/swing/gui/ComponentPopupMenu.java
index 36dd0df4..060cfaaa 100644
--- a/diylc/diylc-swing/src/main/java/org/diylc/swing/gui/ComponentPopupMenu.java
+++ b/diylc/diylc-swing/src/main/java/org/diylc/swing/gui/ComponentPopupMenu.java
@@ -351,7 +351,7 @@ public class ComponentPopupMenu extends TranslatedPopupMenu implements Clipboard
     }
     
     applyMenu.setEnabled(true);
-    List<Component> datasheetItems = ComponentButtonFactory.createDatasheetItems(plugInPort, componentType, new ArrayList<String>(), model -> {
+    List<Component> datasheetItems = ComponentButtonFactory.createDatasheetItems(plugInPort, componentType, new ArrayList<String>(), false, model -> {
       LOG.info("Applying datasheet model " + String.join(", ", model));      
       plugInPort.applyModelToSelection(model);
     });
diff --git a/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/toolbox/ComponentButtonFactory.java b/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/toolbox/ComponentButtonFactory.java
index d72ed16c..de6eaf77 100644
--- a/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/toolbox/ComponentButtonFactory.java
+++ b/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/toolbox/ComponentButtonFactory.java
@@ -42,9 +42,9 @@ import javax.swing.JMenu;
 import javax.swing.JMenuItem;
 import javax.swing.JOptionPane;
 import javax.swing.JPopupMenu;
+import javax.swing.MenuSelectionManager;
 import javax.swing.SwingConstants;
 import javax.swing.SwingUtilities;
-import javax.swing.border.Border;
 import javax.swing.border.EmptyBorder;
 import javax.swing.event.MenuEvent;
 import javax.swing.event.MenuListener;
@@ -59,6 +59,7 @@ import org.diylc.common.IPlugInPort;
 import org.diylc.common.IBlockProcessor.InvalidBlockException;
 import org.diylc.core.IDIYComponent;
 import org.diylc.core.Template;
+import org.diylc.lang.LangUtil;
 import org.diylc.utils.IconLoader;
 
 /**
@@ -170,34 +171,14 @@ public class ComponentButtonFactory {
       }
     });
 
-    String defaultVariant = plugInPort.getDefaultVariant(componentType);
-
-    JLabel label =
-        new JLabel(variant.getName().equals(defaultVariant) ? IconLoader.PinGreen.getIcon()
-            : IconLoader.PinGrey.getIcon());
-    label.setToolTipText(variant.getName().equals(defaultVariant) ? "Remove default variant"
-        : "Set default variant");
-    label.addMouseListener(new MouseAdapter() {
-
-      @Override
-      public void mouseClicked(MouseEvent e) {
-        // Hide the menu
-        Container c = item.getParent();
-        if (c != null && c instanceof JPopupMenu) {
-          JPopupMenu m = (JPopupMenu) c;
-          m.setVisible(false);
-        }
-        plugInPort.setDefaultVariant(componentType, variant.getName());
-        e.consume();
-      }
-    });
-    Border margin = new EmptyBorder(4, 0, 0, 0);
-    label.setBorder(margin);
+    boolean isDefault = variant.getName().equals(plugInPort.getDefaultVariant(componentType));
     item.setLayout(new FlowLayout(FlowLayout.RIGHT, 0, 0));
-    item.add(label);
+    item.add(createDefaultPin(isDefault,
+        isDefault ? "Remove default variant" : "Set default variant",
+        () -> plugInPort.setDefaultVariant(componentType, variant.getName())));
 
-    label = new JLabel(IconLoader.Garbage.getIcon());
-    label.setToolTipText("Delete variant");
+    JLabel label = new JLabel(IconLoader.Garbage.getIcon());
+    label.setToolTipText(LangUtil.translate("Delete variant"));
     label.addMouseListener(new MouseAdapter() {
 
       @Override
@@ -209,8 +190,10 @@ public class ComponentButtonFactory {
           m.setVisible(false);
         }
         int result = JOptionPane.showConfirmDialog(SwingUtilities.getRoot(item),
-            "Are you sure you want to delete variant \"" + variant.getName() + "\"", "Delete",
-            JOptionPane.YES_NO_OPTION, JOptionPane.WARNING_MESSAGE);
+            String.format(LangUtil.translate("Are you sure you want to delete variant \"%s\"?"),
+                variant.getName()),
+            LangUtil.translate("Delete"), JOptionPane.YES_NO_OPTION,
+            JOptionPane.WARNING_MESSAGE);
         if (result != JOptionPane.YES_OPTION) {
           return;
         }
@@ -218,15 +201,18 @@ public class ComponentButtonFactory {
         e.consume();
       }
     });
-    margin = new EmptyBorder(4, 2, 0, 0);
-    label.setBorder(margin);
-    item.setLayout(new FlowLayout(FlowLayout.RIGHT, 0, 0));
+    label.setBorder(new EmptyBorder(4, 2, 0, 0));
     item.add(label);
     return item;
   }
 
+  /**
+   * @param showDefaultPin whether model items get the pin that makes a model the default of the
+   *        type; only meaningful where the items place a new component
+   */
   public static List<Component> createDatasheetItems(final IPlugInPort plugInPort,
-      final ComponentType componentType, List<String> path, Consumer<String[]> modelConsumer) {
+      final ComponentType componentType, List<String> path, boolean showDefaultPin,
+      Consumer<String[]> modelConsumer) {
     int depth = path.size();
     List<String[]> datasheet = componentType.getDatasheet();
     if (datasheet == null) {
@@ -253,7 +239,8 @@ public class ComponentButtonFactory {
             submenu.removeAll();
             List<String> newPath = new ArrayList<String>(path);
             newPath.add(value);
-            List<Component> childItems = createDatasheetItems(plugInPort, componentType, newPath, modelConsumer);
+            List<Component> childItems = createDatasheetItems(plugInPort, componentType, newPath,
+                showDefaultPin, modelConsumer);
             if (childItems.size() > MAX_MENU_ITEMS) {
               List<List<Component>> partitions = Lists.partition(childItems, MAX_MENU_ITEMS);
               for (List<Component> partition : partitions) {
@@ -293,15 +280,24 @@ public class ComponentButtonFactory {
         return (Component) submenu;
       }
 
-      JMenuItem item = new JMenuItem(value);
+      Optional<String[]> findFirst =
+          filteredDatasheet.stream().filter(line -> line[depth].equals(value)).findFirst();
+
+      final JMenuItem item = new JMenuItem(value) {
+
+        private static final long serialVersionUID = 1L;
+
+        // Customize item size to fit the pin
+        public java.awt.Dimension getPreferredSize() {
+          Dimension d = super.getPreferredSize();
+          return new Dimension(d.width + (showDefaultPin ? 16 : 0), d.height);
+        }
+      };
 
       item.addActionListener(new ActionListener() {
 
         @Override
         public void actionPerformed(ActionEvent e) {
-          Optional<String[]> findFirst =
-              filteredDatasheet.stream().filter(line -> line[depth].equals(value)).findFirst();
-
           if (findFirst.isPresent()) {
             modelConsumer.accept(findFirst.get());            
           } else {
@@ -310,6 +306,15 @@ public class ComponentButtonFactory {
         }
       });
 
+      if (showDefaultPin && findFirst.isPresent()) {
+        String[] model = findFirst.get();
+        boolean isDefault = plugInPort.isDefaultModel(componentType, model);
+        item.setLayout(new FlowLayout(FlowLayout.RIGHT, 0, 0));
+        item.add(createDefaultPin(isDefault,
+            isDefault ? "Remove default model" : "Set default model",
+            () -> plugInPort.setDefaultModel(componentType, model)));
+      }
+
       return (Component) item;
     }).collect(Collectors.toList());
   }
@@ -347,4 +352,28 @@ public class ComponentButtonFactory {
     });
     return button;
   }
+
+  private static JLabel createDefaultPin(boolean isDefault, String tooltip,
+      final Runnable toggle) {
+    JLabel label = new JLabel(
+        isDefault ? IconLoader.PinGreen.getIcon() : IconLoader.PinGrey.getIcon());
+    label.setToolTipText(LangUtil.translate(tooltip));
+    label.addMouseListener(new MouseAdapter() {
+
+      // a click is not reported when the pointer moves between press and release, which happens
+      // easily on a 16px icon, so react to the release instead, as menu items themselves do
+      @Override
+      public void mouseReleased(MouseEvent e) {
+        if (!label.contains(e.getPoint())) {
+          return;
+        }
+        // closes the whole cascade, not just the submenu that holds a datasheet model
+        MenuSelectionManager.defaultManager().clearSelectedPath();
+        toggle.run();
+        e.consume();
+      }
+    });
+    label.setBorder(new EmptyBorder(4, 0, 0, 0));
+    return label;
+  }
 }
diff --git a/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/toolbox/ComponentTabbedPane.java b/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/toolbox/ComponentTabbedPane.java
index 07db6810..6ead2e58 100644
--- a/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/toolbox/ComponentTabbedPane.java
+++ b/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/toolbox/ComponentTabbedPane.java
@@ -508,7 +508,7 @@ class ComponentTabbedPane extends JTabbedPane {
           variantPopup.add(new JSeparator());
           
           if (componentType.getDatasheet() != null && !componentType.getDatasheet().isEmpty()) {
-            List<Component> items = ComponentButtonFactory.createDatasheetItems(plugInPort, componentType, new ArrayList<String>(), model -> {
+            List<Component> items = ComponentButtonFactory.createDatasheetItems(plugInPort, componentType, new ArrayList<String>(), true, model -> {
               LOG.info("Creating datasheet model " + String.join(", ", model));
               plugInPort.setNewComponentTypeSlot(componentType, null, model, false);
             });
diff --git a/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/tree/TreePanel.java b/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/tree/TreePanel.java
index 2c165fee..08a4f7bb 100644
--- a/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/tree/TreePanel.java
+++ b/diylc/diylc-swing/src/main/java/org/diylc/swing/plugins/tree/TreePanel.java
@@ -610,7 +610,7 @@ public class TreePanel extends JPanel {
       boolean showEmpty) {
     if (componentType.getDatasheet() != null) {
       List<Component> items = ComponentButtonFactory.createDatasheetItems(plugInPort,
-          componentType, new ArrayList<String>(), model -> {
+          componentType, new ArrayList<String>(), true, model -> {
             LOG.info("Creating datasheet model " + String.join(", ", model));
             plugInPort.setNewComponentTypeSlot(componentType, null, model, false);
           });
diff --git a/diylc/diylc-swing/src/main/resources/lang/Deutsch.txt b/diylc/diylc-swing/src/main/resources/lang/Deutsch.txt
index 595f3d51..66a7b264 100644
--- a/diylc/diylc-swing/src/main/resources/lang/Deutsch.txt
+++ b/diylc/diylc-swing/src/main/resources/lang/Deutsch.txt
@@ -722,3 +722,10 @@ All|Alle
 Front and Back|Vorne und hinten
 Click to choose from %s variants|Klicken, um aus %s Varianten zu wählen
 Flange|Flansch
+Set default variant|Als Standardvariante festlegen
+Remove default variant|Standardvariante entfernen
+Delete variant|Variante löschen
+Are you sure you want to delete variant "%s"?|Möchten Sie die Variante "%s" wirklich löschen?
+Delete|Löschen
+Set default model|Als Standardmodell festlegen
+Remove default model|Standardmodell entfernen
diff --git a/diylc/diylc-swing/src/main/resources/lang/English.txt b/diylc/diylc-swing/src/main/resources/lang/English.txt
index ec8e8ac9..f9e1dc6e 100644
--- a/diylc/diylc-swing/src/main/resources/lang/English.txt
+++ b/diylc/diylc-swing/src/main/resources/lang/English.txt
@@ -715,3 +715,10 @@ All
 Front and Back
 Click to choose from %s variants
 Flange
+Set default variant
+Remove default variant
+Delete variant
+Are you sure you want to delete variant "%s"?
+Delete
+Set default model
+Remove default model
diff --git a/diylc/diylc-swing/src/main/resources/lang/Español.txt b/diylc/diylc-swing/src/main/resources/lang/Español.txt
index a7091405..0af19b7e 100644
--- a/diylc/diylc-swing/src/main/resources/lang/Español.txt
+++ b/diylc/diylc-swing/src/main/resources/lang/Español.txt
@@ -718,3 +718,10 @@ All|Todos
 Front and Back|Frente y parte trasera
 Click to choose from %s variants|Haga clic para elegir entre %s variantes
 Flange|Brida
+Set default variant|Establecer como variante predeterminada
+Remove default variant|Quitar variante predeterminada
+Delete variant|Eliminar variante
+Are you sure you want to delete variant "%s"?|¿Seguro que desea eliminar la variante "%s"?
+Delete|Eliminar
+Set default model|Establecer como modelo predeterminado
+Remove default model|Quitar modelo predeterminado
diff --git a/diylc/diylc-swing/src/main/resources/lang/Français.txt b/diylc/diylc-swing/src/main/resources/lang/Français.txt
index f8ee2449..f37f90fa 100644
--- a/diylc/diylc-swing/src/main/resources/lang/Français.txt
+++ b/diylc/diylc-swing/src/main/resources/lang/Français.txt
@@ -717,3 +717,10 @@ All|Tous
 Front and Back|Avant et arrière
 Click to choose from %s variants|Cliquez pour choisir parmi %s variantes
 Flange|Collerette
+Set default variant|Définir comme variante par défaut
+Remove default variant|Retirer la variante par défaut
+Delete variant|Supprimer la variante
+Are you sure you want to delete variant "%s"?|Voulez-vous vraiment supprimer la variante "%s" ?
+Delete|Supprimer
+Set default model|Définir comme modèle par défaut
+Remove default model|Retirer le modèle par défaut
diff --git a/diylc/diylc-swing/src/main/resources/lang/Italiano.txt b/diylc/diylc-swing/src/main/resources/lang/Italiano.txt
index b13a8f59..a4f36556 100644
--- a/diylc/diylc-swing/src/main/resources/lang/Italiano.txt
+++ b/diylc/diylc-swing/src/main/resources/lang/Italiano.txt
@@ -719,3 +719,10 @@ All|Tutti
 Front and Back|Fronte e retro
 Click to choose from %s variants|Fai clic per scegliere tra %s varianti
 Flange|Flangia
+Set default variant|Imposta come variante predefinita
+Remove default variant|Rimuovi variante predefinita
+Delete variant|Elimina variante
+Are you sure you want to delete variant "%s"?|Eliminare davvero la variante "%s"?
+Delete|Elimina
+Set default model|Imposta come modello predefinito
+Remove default model|Rimuovi modello predefinito
diff --git a/diylc/diylc-swing/src/main/resources/lang/Nederlands.txt b/diylc/diylc-swing/src/main/resources/lang/Nederlands.txt
index a17e109b..f21d47a3 100644
--- a/diylc/diylc-swing/src/main/resources/lang/Nederlands.txt
+++ b/diylc/diylc-swing/src/main/resources/lang/Nederlands.txt
@@ -723,3 +723,10 @@ All|Alle
 Front and Back|Voor- en achterkant
 Click to choose from %s variants|Klik om te kiezen uit %s varianten
 Flange|Flens
+Set default variant|Instellen als standaardvariant
+Remove default variant|Standaardvariant verwijderen
+Delete variant|Variant verwijderen
+Are you sure you want to delete variant "%s"?|Weet u zeker dat u variant "%s" wilt verwijderen?
+Delete|Verwijderen
+Set default model|Instellen als standaardmodel
+Remove default model|Standaardmodel verwijderen
diff --git a/diylc/diylc-swing/src/main/resources/lang/Português.txt b/diylc/diylc-swing/src/main/resources/lang/Português.txt
index 7fb51e7c..d4d3c1f5 100644
--- a/diylc/diylc-swing/src/main/resources/lang/Português.txt
+++ b/diylc/diylc-swing/src/main/resources/lang/Português.txt
@@ -718,3 +718,10 @@ All|Todos
 Front and Back|Frente e traseira
 Click to choose from %s variants|Clique para escolher entre %s variantes
 Flange|Flange
+Set default variant|Definir como variante padrão
+Remove default variant|Remover variante padrão
+Delete variant|Excluir variante
+Are you sure you want to delete variant "%s"?|Tem certeza de que deseja excluir a variante "%s"?
+Delete|Excluir
+Set default model|Definir como modelo padrão
+Remove default model|Remover modelo padrão
diff --git a/diylc/diylc-swing/src/main/resources/lang/Srpski.txt b/diylc/diylc-swing/src/main/resources/lang/Srpski.txt
index d723b9a9..6c17ce23 100644
--- a/diylc/diylc-swing/src/main/resources/lang/Srpski.txt
+++ b/diylc/diylc-swing/src/main/resources/lang/Srpski.txt
@@ -714,3 +714,10 @@ All|Sve
 Front and Back|Prednja i zadnja
 Click to choose from %s variants|Kliknite da izaberete jednu od %s varijanti
 Flange|Obod
+Set default variant|Postavi kao podrazumevanu varijantu
+Remove default variant|Ukloni podrazumevanu varijantu
+Delete variant|Obriši varijantu
+Are you sure you want to delete variant "%s"?|Da li ste sigurni da želite da obrišete varijantu "%s"?
+Delete|Obriši
+Set default model|Postavi kao podrazumevani model
+Remove default model|Ukloni podrazumevani model
diff --git a/diylc/diylc-swing/src/main/resources/lang/हिंदी.txt b/diylc/diylc-swing/src/main/resources/lang/हिंदी.txt
index 60e7f10b..813bd70b 100644
--- a/diylc/diylc-swing/src/main/resources/lang/हिंदी.txt
+++ b/diylc/diylc-swing/src/main/resources/lang/हिंदी.txt
@@ -716,3 +716,10 @@ All|सभी
 Front and Back|आगे और पीछे
 Click to choose from %s variants|%s वेरिएंट में से चुनने के लिए क्लिक करें
 Flange|फ़्लैंज
+Set default variant|डिफ़ॉल्ट वेरिएंट सेट करें
+Remove default variant|डिफ़ॉल्ट वेरिएंट हटाएँ
+Delete variant|वेरिएंट हटाएँ
+Are you sure you want to delete variant "%s"?|क्या आप वाकई वेरिएंट "%s" हटाना चाहते हैं?
+Delete|हटाएँ
+Set default model|डिफ़ॉल्ट मॉडल सेट करें
+Remove default model|डिफ़ॉल्ट मॉडल हटाएँ
diff --git a/diylc/diylc-swing/src/main/resources/lang/简体中文.txt b/diylc/diylc-swing/src/main/resources/lang/简体中文.txt
index ece88f72..6883ac1c 100644
--- a/diylc/diylc-swing/src/main/resources/lang/简体中文.txt
+++ b/diylc/diylc-swing/src/main/resources/lang/简体中文.txt
@@ -716,3 +716,10 @@ All|全部
 Front and Back|前后
 Click to choose from %s variants|点击从 %s 个变体中选择
 Flange|法兰
+Set default variant|设为默认变体
+Remove default variant|取消默认变体
+Delete variant|删除变体
+Are you sure you want to delete variant "%s"?|确定要删除变体“%s”吗？
+Delete|删除
+Set default model|设为默认型号
+Remove default model|取消默认型号
diff --git a/diylc/docs/plans/default-datasheet-model.md b/diylc/docs/plans/default-datasheet-model.md
new file mode 100644
index 00000000..fcb67520
--- /dev/null
+++ b/diylc/docs/plans/default-datasheet-model.md
@@ -0,0 +1,72 @@
+# Default Datasheet Model
+
+Letting a datasheet model be pinned as a component's default, the way a user-defined variant can.
+
+## 1. Goal
+
+A saved variant in a component's drop-down has two mini buttons: a pin that makes it the default,
+so a plain click on the component in the toolbox or tree places that variant, and a bin that
+deletes it. Datasheet models (the TO-1 transistors, resistor series, IC part numbers, ...) sit in
+the same drop-down but have no pin, so a user who always places a 2N3904 has to walk the submenu
+every time. Datasheet model leaves get the same pin, and only one default can exist per component
+type, whether it is a variant or a model.
+
+## 2. Current state
+
+| Piece | Where | What it does |
+| --- | --- | --- |
+| Storage | `IVariantProcessor.DEFAULT_TEMPLATES_KEY` (`"defaultTemplates"`) | A `Map<String, String>` in the configuration: component class name (or the legacy `category.name` key) to the default variant's name. |
+| Write | `Presenter.setDefaultVariant` | Toggles: clicking the current default removes it, anything else replaces it. The logic lives in `Presenter`, unlike the read side. |
+| Read | `VariantManager.getDefaultVariant` | Looks up the class-name key, then the legacy key. |
+| Apply | `Presenter.setNewComponentTypeSlot` | When called with no template, finds the variant named by the default and uses it. |
+| UI | `ComponentButtonFactory.createVariantItem` | Adds the pin (`IconLoader.PinGreen` / `PinGrey`) and bin labels to a variant's `JMenuItem`; the pin hides the popup and calls `setDefaultVariant`. |
+| Model items | `ComponentButtonFactory.createDatasheetItems` | Builds the datasheet submenus recursively; leaves are plain `JMenuItem`s that hand the row to a `Consumer<String[]>`. |
+
+`createDatasheetItems` has three callers: the variants button in the component tree
+(`TreePanel.addVariantItems`), the toolbox drop-down (`ComponentTabbedPane`), and the canvas
+right-click "apply model" submenu (`ComponentPopupMenu`), which applies a model to the selection
+rather than placing a new component.
+
+Because the map holds one value per component type, "only one default" already holds as long as
+models are written to the same map.
+
+## 3. Design decisions
+
+| # | Decision | Choice | Rationale |
+| --- | --- | --- | --- |
+| D1 | Storage | Same `defaultTemplates` map and key. A model default is stored as the string `datasheet:` followed by the row's menu path, the first `datasheetCreationStepCount` columns joined by `\|`, e.g. `datasheet:BJT (NPN)\|2N3904` | One entry per type means pinning a model replaces a pinned variant and the other way round, with no extra bookkeeping. The menu path is exactly what identifies a leaf in `createDatasheetItems` (it already resolves a click by matching the path and taking the first row). No datasheet contains `\|` today. |
+| D2 | Compatibility | No config migration. An older DIYLC reading a `datasheet:` value finds no variant of that name and places the component with no default | The configuration is shared between installed versions, so the value has to be harmless to old readers, and it is. |
+| D3 | Name collision | The `datasheet:` prefix | A variant would have to be named `datasheet:...` to collide. |
+| D4 | Core API | `IVariantProcessor` gains `setDefaultModel(ComponentType, String[] model)` and `isDefaultModel(ComponentType, String[] model)`; encoding and decoding stay in `VariantManager`. `Presenter.setDefaultVariant`'s body moves into `VariantManager` so both toggles share one write path; `Presenter` only delegates | Keeps the string format out of Swing, and keeps new logic out of `Presenter`. |
+| D5 | Applying the default | In `setNewComponentTypeSlot`, when both template and model are null: if the default is a model, resolve its path against `componentType.getDatasheet()` and pass that row as the model; otherwise the current variant lookup. A path that no longer matches any row (a model dropped from a datasheet) falls through to no default | Same entry point every toolbox click, tree click, double click and drag already uses. Picking a model from the menu no longer also picks up a pinned variant's shape, which it used to because the lookup only checked for a missing template. |
+| D6 | Pin in the UI | Only on datasheet **leaves**, and only where the item places a new component: `createDatasheetItems` gets a `boolean showDefaultPin`, true from `TreePanel` and `ComponentTabbedPane`, false from `ComponentPopupMenu` | A default makes no sense in "apply model to selection". |
+| D7 | Shared pin code | The pin `JLabel` (icon, tooltip, hide-popup-then-toggle listener, border) is extracted from `createVariantItem` into one private helper used by both items; model leaves get only the pin, so their extra preferred width is 16 rather than 32 | Variant and model pins then look and behave identically. |
+| D8 | Tooltips | "Set default model" / "Remove default model", and the previously hard-coded "Set default variant", "Remove default variant", "Delete variant" and the delete confirmation, all through `LangUtil.translate`, in `English.txt` and all nine translations | Required for new UI text; the variant strings sit in the same code and are localized with it. |
+| D9 | Visibility of a nested default | Only the pinned leaf shows a green pin; the submenus leading to it do not | Green pins that cannot be clicked next to the one that can would be confusing. Pinning another model or a variant replaces the default anyway. |
+
+## 4. Changes by file
+
+| Module | File | Change |
+| --- | --- | --- |
+| core | `IVariantProcessor` | Add `setDefaultModel`, `isDefaultModel`. |
+| core | `VariantManager` | Add `setDefaultVariant` (moved from `Presenter`), `setDefaultModel`, `isDefaultModel`, `getDefaultModel(ComponentType)` returning the resolved row or null, and the private encode helper. |
+| core | `Presenter` | `setDefaultVariant` delegates; add the two delegating model methods; extend the default lookup in `setNewComponentTypeSlot` per D5. |
+| swing | `ComponentButtonFactory` | Extract the pin helper; pin on datasheet leaves behind `showDefaultPin`, threaded through the recursion. |
+| swing | `TreePanel`, `ComponentTabbedPane`, `ComponentPopupMenu` | Pass `showDefaultPin` (true, true, false). |
+| swing | `lang/*.txt` | Seven new keys in all ten files, each file's own line endings. |
+| core | `update.xml` | One `NEW_FEATURE` line in the unreleased 6.10.0 block. |
+
+## 5. Tests
+
+`VariantManagerTest` in `diylc-core` with a map-backed `IConfigurationManager`:
+
+- pinning a model stores the prefixed path and `isDefaultModel` reports it;
+- pinning the same model again clears it;
+- pinning a model replaces a pinned variant and pinning a variant replaces a pinned model;
+- `getDefaultModel` resolves the row, and returns null when the path is no longer in the datasheet;
+- a legacy `category.name` key is still read and is removed on the next write.
+
+Verification: `mvn -q -pl diylc-core -am test`, then `mvn -q -pl diylc-swing -am compile`, then a
+manual check in the running app (pin a TO-1 model, click the toolbox button, confirm the part;
+pin a variant and confirm the model's pin turns grey). No rendering, serialization or netlist
+change, so no regression run is needed.