diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/ui/sourcelookup/SourceLookupBlock.java b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/ui/sourcelookup/SourceLookupBlock.java
index 71e3a5334b9..76004c387e6 100644
--- a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/ui/sourcelookup/SourceLookupBlock.java
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/ui/sourcelookup/SourceLookupBlock.java
@@ -323,8 +323,8 @@ public class SourceLookupBlock
 		{
 			getLaunchConfigurationDialog().updateMessage();
 			getLaunchConfigurationDialog().updateButtons();
+			fIsDirty = false;
 		}
-		fIsDirty = false;
 	}
 
 	public ILaunchConfigurationDialog getLaunchConfigurationDialog()