diff --git a/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/views/launch/LaunchView.java b/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/views/launch/LaunchView.java
index e3ced45..3dfb9c3 100644
--- a/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/views/launch/LaunchView.java
+++ b/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/views/launch/LaunchView.java
@@ -670,6 +670,7 @@
 		if (fSourceLookupJob == null) {
 			fSourceLookupJob = new SourceLookupJob();
 		}
+		setSourceLookupResult(null);
 		fSourceLookupJob.schedule();
 	}