Merge branch 'DrawLineOnCanvas' of https://github.com/jogibear9988/SharpDevelop into DrawLineOnCanvas

.gitignore

@@ -23,3 +23,10 @@ bin/
 /src/AddIns/Misc/PackageManagement/Packages/AvalonEdit/lib
 /packages/
 /src/Tools/ResGet/*.log
+
+
+*.ide/
+*.sdsettings
+*.DotSettings.user
+*.suo
+.DS_Store

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.XamlDom/Project/XamlProperty.cs

@@ -203,8 +203,10 @@ namespace ICSharpCode.WpfDesign.XamlDom
 			ResetInternal();
 
 			propertyValue = value;
-			propertyValue.ParentProperty = this;
+			if (propertyValue != null) {
-			propertyValue.AddNodeTo(this);
+				propertyValue.ParentProperty = this;
+				propertyValue.AddNodeTo(this);
+			}
 			UpdateValueOnInstance();
 
 			ParentObject.OnPropertyChanged(this);