diff --git a/diylc/diylc-core/src/org/diylc/components/AbstractLeadedComponent.java b/diylc/diylc-core/src/org/diylc/components/AbstractLeadedComponent.java
index 3e5a49cc..7d67ace4 100644
--- a/diylc/diylc-core/src/org/diylc/components/AbstractLeadedComponent.java
+++ b/diylc/diylc-core/src/org/diylc/components/AbstractLeadedComponent.java
@@ -41,6 +41,7 @@ import org.diylc.core.Project;
 import org.diylc.core.Theme;
 import org.diylc.core.VisibilityPolicy;
 import org.diylc.core.annotations.EditableProperty;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -439,7 +440,7 @@ public abstract class AbstractLeadedComponent<T> extends AbstractTransparentComp
     this.borderColor = borderColor;
   }
 
-  @EditableProperty(name = "Length", defaultable = true)
+  @EditableProperty(name = "Length", defaultable = true, validatorClass = PositiveMeasureValidator.class)
   public Size getLength() {
     return length;
   }
@@ -448,7 +449,7 @@ public abstract class AbstractLeadedComponent<T> extends AbstractTransparentComp
     this.length = length;
   }
 
-  @EditableProperty(name = "Width", defaultable = true)
+  @EditableProperty(name = "Width", defaultable = true, validatorClass = PositiveMeasureValidator.class)
   public Size getWidth() {
     return width;
   }
diff --git a/diylc/diylc-library/lib/diylc-core.jar b/diylc/diylc-library/lib/diylc-core.jar
index 7f840a59..d01d0160 100644
Binary files a/diylc/diylc-library/lib/diylc-core.jar and b/diylc/diylc-library/lib/diylc-core.jar differ
diff --git a/diylc/diylc-library/src/org/diylc/components/boards/MarshallPerfBoard.java b/diylc/diylc-library/src/org/diylc/components/boards/MarshallPerfBoard.java
index 4fd49460..a3de525a 100644
--- a/diylc/diylc-library/src/org/diylc/components/boards/MarshallPerfBoard.java
+++ b/diylc/diylc-library/src/org/diylc/components/boards/MarshallPerfBoard.java
@@ -26,7 +26,7 @@ import java.awt.Color;
 import java.awt.Graphics2D;
 import java.awt.Point;
 import java.awt.Shape;
-
+
 import org.diylc.common.SimpleComponentTransformer;
 import org.diylc.core.ComponentState;
 import org.diylc.core.IDIYComponent;
@@ -36,6 +36,7 @@ import org.diylc.core.annotations.BomPolicy;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
 import org.diylc.core.annotations.KeywordPolicy;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -95,7 +96,7 @@ public class MarshallPerfBoard extends AbstractBoard {
     }
   }
 
-  @EditableProperty
+  @EditableProperty(validatorClass = PositiveMeasureValidator.class)
   public Size getSpacing() {
     return spacing;
   }
diff --git a/diylc/diylc-library/src/org/diylc/components/boards/PerfBoard.java b/diylc/diylc-library/src/org/diylc/components/boards/PerfBoard.java
index cbb20f53..c74e35eb 100644
--- a/diylc/diylc-library/src/org/diylc/components/boards/PerfBoard.java
+++ b/diylc/diylc-library/src/org/diylc/components/boards/PerfBoard.java
@@ -26,7 +26,7 @@ import java.awt.Color;
 import java.awt.Graphics2D;
 import java.awt.Point;
 import java.awt.Shape;
-
+
 import org.diylc.common.SimpleComponentTransformer;
 import org.diylc.core.ComponentState;
 import org.diylc.core.IDIYComponent;
@@ -36,6 +36,7 @@ import org.diylc.core.annotations.BomPolicy;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
 import org.diylc.core.annotations.KeywordPolicy;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -104,7 +105,7 @@ public class PerfBoard extends AbstractBoard {
     this.padColor = padColor;
   }
 
-  @EditableProperty
+  @EditableProperty(validatorClass = PositiveMeasureValidator.class)
   public Size getSpacing() {
     return spacing;
   }
diff --git a/diylc/diylc-library/src/org/diylc/components/boards/TerminalStrip.java b/diylc/diylc-library/src/org/diylc/components/boards/TerminalStrip.java
index d1f64211..7eb3d07a 100644
--- a/diylc/diylc-library/src/org/diylc/components/boards/TerminalStrip.java
+++ b/diylc/diylc-library/src/org/diylc/components/boards/TerminalStrip.java
@@ -29,7 +29,7 @@ import java.awt.Point;
 import java.awt.geom.Area;
 import java.awt.geom.Ellipse2D;
 import java.awt.geom.RoundRectangle2D;
-
+
 import org.diylc.appframework.miscutils.ConfigurationManager;
 import org.diylc.common.IPlugInPort;
 import org.diylc.common.ObjectCache;
@@ -45,6 +45,7 @@ import org.diylc.core.VisibilityPolicy;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
 import org.diylc.core.annotations.KeywordPolicy;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -115,7 +116,7 @@ public class TerminalStrip extends AbstractTransparentComponent<String> {
     body = null;
   }
 
-  @EditableProperty(name = "Terminal spacing")
+  @EditableProperty(name = "Terminal Spacing", validatorClass = PositiveMeasureValidator.class)
   public Size getTerminalSpacing() {
     return terminalSpacing;
   }
@@ -127,7 +128,7 @@ public class TerminalStrip extends AbstractTransparentComponent<String> {
     body = null;
   }
 
-  @EditableProperty(name = "Hole spacing")
+  @EditableProperty(name = "Hole Spacing", validatorClass = PositiveMeasureValidator.class)
   public Size getHoleSpacing() {
     return holeSpacing;
   }
@@ -139,7 +140,7 @@ public class TerminalStrip extends AbstractTransparentComponent<String> {
     body = null;
   }
 
-  @EditableProperty(name = "Center terminal")
+  @EditableProperty(name = "Center Terminal")
   public boolean getCenterHole() {
     return centerHole;
   }
@@ -151,7 +152,7 @@ public class TerminalStrip extends AbstractTransparentComponent<String> {
     body = null;
   }
 
-  @EditableProperty(name = "Board width")
+  @EditableProperty(name = "Board Width", validatorClass = PositiveMeasureValidator.class)
   public Size getBoardWidth() {
     return boardWidth;
   }
diff --git a/diylc/diylc-library/src/org/diylc/components/boards/TriPadBoard.java b/diylc/diylc-library/src/org/diylc/components/boards/TriPadBoard.java
index ab77cd15..c414a594 100644
--- a/diylc/diylc-library/src/org/diylc/components/boards/TriPadBoard.java
+++ b/diylc/diylc-library/src/org/diylc/components/boards/TriPadBoard.java
@@ -27,7 +27,7 @@ import java.awt.Composite;
 import java.awt.Graphics2D;
 import java.awt.Point;
 import java.awt.Shape;
-
+
 import org.diylc.common.SimpleComponentTransformer;
 import org.diylc.common.OrientationHV;
 import org.diylc.core.ComponentState;
@@ -37,6 +37,7 @@ import org.diylc.core.Project;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
 import org.diylc.core.annotations.KeywordPolicy;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -162,7 +163,7 @@ public class TriPadBoard extends AbstractBoard {
     }
   }
 
-  @EditableProperty(name = "Strip color")
+  @EditableProperty(name = "Strip Color")
   public Color getStripColor() {
     return stripColor;
   }
@@ -171,7 +172,7 @@ public class TriPadBoard extends AbstractBoard {
     this.stripColor = padColor;
   }
 
-  @EditableProperty
+  @EditableProperty(validatorClass = PositiveMeasureValidator.class)
   public Size getSpacing() {
     return spacing;
   }
diff --git a/diylc/diylc-library/src/org/diylc/components/boards/VeroBoard.java b/diylc/diylc-library/src/org/diylc/components/boards/VeroBoard.java
index 18e32707..d7c9748d 100644
--- a/diylc/diylc-library/src/org/diylc/components/boards/VeroBoard.java
+++ b/diylc/diylc-library/src/org/diylc/components/boards/VeroBoard.java
@@ -27,7 +27,7 @@ import java.awt.Composite;
 import java.awt.Graphics2D;
 import java.awt.Point;
 import java.awt.Shape;
-
+
 import org.diylc.common.SimpleComponentTransformer;
 import org.diylc.common.OrientationHV;
 import org.diylc.core.ComponentState;
@@ -38,6 +38,7 @@ import org.diylc.core.annotations.BomPolicy;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
 import org.diylc.core.annotations.KeywordPolicy;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -122,7 +123,7 @@ public class VeroBoard extends AbstractBoard {
     }
   }
 
-  @EditableProperty(name = "Strip color")
+  @EditableProperty(name = "Strip Color")
   public Color getStripColor() {
     return stripColor;
   }
@@ -131,7 +132,7 @@ public class VeroBoard extends AbstractBoard {
     this.stripColor = padColor;
   }
 
-  @EditableProperty
+  @EditableProperty(validatorClass = PositiveMeasureValidator.class)
   public Size getSpacing() {
     return spacing;
   }
diff --git a/diylc/diylc-library/src/org/diylc/components/connectivity/Dot.java b/diylc/diylc-library/src/org/diylc/components/connectivity/Dot.java
index e414649c..4df529e2 100644
--- a/diylc/diylc-library/src/org/diylc/components/connectivity/Dot.java
+++ b/diylc/diylc-library/src/org/diylc/components/connectivity/Dot.java
@@ -24,7 +24,7 @@ package org.diylc.components.connectivity;
 import java.awt.Color;
 import java.awt.Graphics2D;
 import java.awt.Point;
-
+
 import org.diylc.common.SimpleComponentTransformer;
 import org.diylc.components.AbstractComponent;
 import org.diylc.core.ComponentState;
@@ -35,6 +35,7 @@ import org.diylc.core.VisibilityPolicy;
 import org.diylc.core.annotations.BomPolicy;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 
@@ -71,7 +72,7 @@ public class Dot extends AbstractComponent<Void> {
     g2d.fillOval((width - diameter) / 2, (height - diameter) / 2, diameter, diameter);
   }
 
-  @EditableProperty
+  @EditableProperty(validatorClass = PositiveMeasureValidator.class)
   public Size getSize() {
     return size;
   }
diff --git a/diylc/diylc-library/src/org/diylc/components/connectivity/Eyelet.java b/diylc/diylc-library/src/org/diylc/components/connectivity/Eyelet.java
index 4004d991..867138d6 100644
--- a/diylc/diylc-library/src/org/diylc/components/connectivity/Eyelet.java
+++ b/diylc/diylc-library/src/org/diylc/components/connectivity/Eyelet.java
@@ -24,7 +24,7 @@ package org.diylc.components.connectivity;
 import java.awt.Color;
 import java.awt.Graphics2D;
 import java.awt.Point;
-
+
 import org.diylc.common.SimpleComponentTransformer;
 import org.diylc.components.AbstractComponent;
 import org.diylc.core.ComponentState;
@@ -36,6 +36,7 @@ import org.diylc.core.annotations.BomPolicy;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
 import org.diylc.core.annotations.KeywordPolicy;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -94,7 +95,7 @@ public class Eyelet extends AbstractComponent<String> {
     g2d.drawOval((width - holeDiameter) / 2, (height - holeDiameter) / 2, holeDiameter, holeDiameter);
   }
 
-  @EditableProperty
+  @EditableProperty(validatorClass = PositiveMeasureValidator.class)
   public Size getSize() {
     return size;
   }
@@ -103,7 +104,7 @@ public class Eyelet extends AbstractComponent<String> {
     this.size = size;
   }
 
-  @EditableProperty(name = "Hole size")
+  @EditableProperty(name = "Hole Size", validatorClass = PositiveMeasureValidator.class)
   public Size getHoleSize() {
     return holeSize;
   }
diff --git a/diylc/diylc-library/src/org/diylc/components/connectivity/SolderPad.java b/diylc/diylc-library/src/org/diylc/components/connectivity/SolderPad.java
index 7a395587..d09f235b 100644
--- a/diylc/diylc-library/src/org/diylc/components/connectivity/SolderPad.java
+++ b/diylc/diylc-library/src/org/diylc/components/connectivity/SolderPad.java
@@ -105,7 +105,7 @@ public class SolderPad extends AbstractComponent<Void> {
     this.size = size;
   }
 
-  @EditableProperty(name = "Hole")
+  @EditableProperty(name = "Hole", validatorClass = PositiveMeasureValidator.class)
   public Size getHoleSize() {
     if (holeSize == null) {
       holeSize = HOLE_SIZE;
diff --git a/diylc/diylc-library/src/org/diylc/components/electromechanical/MiniToggleSwitch.java b/diylc/diylc-library/src/org/diylc/components/electromechanical/MiniToggleSwitch.java
index 5a806f6d..06465d48 100644
--- a/diylc/diylc-library/src/org/diylc/components/electromechanical/MiniToggleSwitch.java
+++ b/diylc/diylc-library/src/org/diylc/components/electromechanical/MiniToggleSwitch.java
@@ -30,7 +30,7 @@ import java.awt.Shape;
 import java.awt.geom.AffineTransform;
 import java.awt.geom.Area;
 import java.awt.geom.RoundRectangle2D;
-
+
 import org.diylc.appframework.miscutils.ConfigurationManager;
 import org.diylc.common.IPlugInPort;
 import org.diylc.common.ObjectCache;
@@ -44,6 +44,7 @@ import org.diylc.core.Theme;
 import org.diylc.core.VisibilityPolicy;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -225,7 +226,7 @@ public class MiniToggleSwitch extends AbstractTransparentComponent<ToggleSwitchT
     body = null;
   }
 
-  @EditableProperty
+  @EditableProperty(validatorClass = PositiveMeasureValidator.class)
   public Size getSpacing() {
     if (spacing == null) {
       spacing = SPACING;
diff --git a/diylc/diylc-library/src/org/diylc/components/passive/TransformerCoil.java b/diylc/diylc-library/src/org/diylc/components/passive/TransformerCoil.java
index 1925d911..7e0b32e7 100644
--- a/diylc/diylc-library/src/org/diylc/components/passive/TransformerCoil.java
+++ b/diylc/diylc-library/src/org/diylc/components/passive/TransformerCoil.java
@@ -26,7 +26,7 @@ import java.awt.Graphics2D;
 import java.awt.Point;
 import java.awt.Shape;
 import java.awt.geom.GeneralPath;
-
+
 import org.diylc.appframework.miscutils.ConfigurationManager;
 import org.diylc.common.IPlugInPort;
 import org.diylc.common.ObjectCache;
@@ -41,6 +41,7 @@ import org.diylc.core.VisibilityPolicy;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
 import org.diylc.core.annotations.KeywordPolicy;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -158,7 +159,7 @@ public class TransformerCoil extends AbstractComponent<org.diylc.core.measures.V
     this.color = color;
   }
 
-  @EditableProperty(name = "Size")
+  @EditableProperty(name = "Size", validatorClass = PositiveMeasureValidator.class)
   public Size getTapSpacing() {
     return tapSpacing;
   }
diff --git a/diylc/diylc-library/src/org/diylc/components/semiconductors/DIL_IC.java b/diylc/diylc-library/src/org/diylc/components/semiconductors/DIL_IC.java
index ebaa3c8d..e619437d 100644
--- a/diylc/diylc-library/src/org/diylc/components/semiconductors/DIL_IC.java
+++ b/diylc/diylc-library/src/org/diylc/components/semiconductors/DIL_IC.java
@@ -33,7 +33,7 @@ import java.awt.geom.Area;
 import java.awt.geom.Ellipse2D;
 import java.awt.geom.Rectangle2D;
 import java.awt.geom.RoundRectangle2D;
-
+
 import org.diylc.appframework.miscutils.ConfigurationManager;
 import org.diylc.common.Display;
 import org.diylc.common.IPlugInPort;
@@ -50,6 +50,7 @@ import org.diylc.core.VisibilityPolicy;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
 import org.diylc.core.annotations.KeywordPolicy;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -134,7 +135,7 @@ public class DIL_IC extends AbstractTransparentComponent<String> {
     body = null;
   }
 
-  @EditableProperty(name = "Pin Spacing")
+  @EditableProperty(name = "Pin Spacing", validatorClass = PositiveMeasureValidator.class)
   public Size getPinSpacing() {
     return pinSpacing;
   }
@@ -146,7 +147,7 @@ public class DIL_IC extends AbstractTransparentComponent<String> {
     body = null;
   }
 
-  @EditableProperty(name = "Row Spacing")
+  @EditableProperty(name = "Row Spacing", validatorClass = PositiveMeasureValidator.class)
   public Size getRowSpacing() {
     return rowSpacing;
   }
diff --git a/diylc/diylc-library/src/org/diylc/components/semiconductors/SIL_IC.java b/diylc/diylc-library/src/org/diylc/components/semiconductors/SIL_IC.java
index b89ad001..48419a8d 100644
--- a/diylc/diylc-library/src/org/diylc/components/semiconductors/SIL_IC.java
+++ b/diylc/diylc-library/src/org/diylc/components/semiconductors/SIL_IC.java
@@ -32,7 +32,7 @@ import java.awt.geom.Area;
 import java.awt.geom.Ellipse2D;
 import java.awt.geom.Rectangle2D;
 import java.awt.geom.RoundRectangle2D;
-
+
 import org.diylc.appframework.miscutils.ConfigurationManager;
 import org.diylc.common.Display;
 import org.diylc.common.IPlugInPort;
@@ -49,6 +49,7 @@ import org.diylc.core.VisibilityPolicy;
 import org.diylc.core.annotations.ComponentDescriptor;
 import org.diylc.core.annotations.EditableProperty;
 import org.diylc.core.annotations.KeywordPolicy;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 import org.diylc.utils.Constants;
@@ -131,7 +132,7 @@ public class SIL_IC extends AbstractTransparentComponent<String> {
     body = null;
   }
 
-  @EditableProperty(name = "Pin Spacing")
+  @EditableProperty(name = "Pin Spacing", validatorClass = PositiveMeasureValidator.class)
   public Size getPinSpacing() {
     return pinSpacing;
   }
diff --git a/diylc/diylc-library/src/org/diylc/components/shapes/AbstractShape.java b/diylc/diylc-library/src/org/diylc/components/shapes/AbstractShape.java
index f44fbe31..818c882a 100644
--- a/diylc/diylc-library/src/org/diylc/components/shapes/AbstractShape.java
+++ b/diylc/diylc-library/src/org/diylc/components/shapes/AbstractShape.java
@@ -23,10 +23,11 @@ package org.diylc.components.shapes;
 
 import java.awt.Color;
 import java.awt.Point;
-
+
 import org.diylc.components.AbstractTransparentComponent;
 import org.diylc.core.VisibilityPolicy;
 import org.diylc.core.annotations.EditableProperty;
+import org.diylc.core.annotations.PositiveMeasureValidator;
 import org.diylc.core.measures.Size;
 import org.diylc.core.measures.SizeUnit;
 
@@ -67,7 +68,7 @@ public abstract class AbstractShape extends AbstractTransparentComponent<Void> {
     this.borderColor = borderColor;
   }
 
-  @EditableProperty(name = "Border thickness")
+  @EditableProperty(name = "Border thickness", validatorClass = PositiveMeasureValidator.class)
   public Size getBorderThickness() {
     return borderThickness;
   }
diff --git a/diylc/diylc-swing/lib/diylc-core.jar b/diylc/diylc-swing/lib/diylc-core.jar
index 7f840a59..d01d0160 100644
Binary files a/diylc/diylc-swing/lib/diylc-core.jar and b/diylc/diylc-swing/lib/diylc-core.jar differ
diff --git a/diylc/diylc-swing/library/main.jar b/diylc/diylc-swing/library/main.jar
index abf1a64f..e86d9b41 100644
Binary files a/diylc/diylc-swing/library/main.jar and b/diylc/diylc-swing/library/main.jar differ
diff --git a/diylc/diylc-swing/update.xml b/diylc/diylc-swing/update.xml
index 728bdd9d..ce4d9229 100644
--- a/diylc/diylc-swing/update.xml
+++ b/diylc/diylc-swing/update.xml
@@ -2170,6 +2170,10 @@
 					<changeType>IMPROVEMENT</changeType>
 					<description>Render resistor color bands and capacitor polarity markings properly when zommed in</description>
 				</org.diylc.appframework.update.Change>	
+				<org.diylc.appframework.update.Change>
+					<changeType>IMPROVEMENT</changeType>
+					<description>Do not allow negative values for properties indicating a size</description>
+				</org.diylc.appframework.update.Change>	
 				<org.diylc.appframework.update.Change>
 					<changeType>BUG_FIX</changeType>
 					<description>Project font gets reverted to "Square721 BT" on Undo</description>