diff --git a/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/views/variables/details/DefaultDetailPane.java b/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/views/variables/details/DefaultDetailPane.java
index d3226f6..1f18e0b 100644
--- a/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/views/variables/details/DefaultDetailPane.java
+++ b/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/views/variables/details/DefaultDetailPane.java
@@ -310,6 +310,9 @@
 								}
 								int topIndex = -1;
 								StyledText styledText = fSourceViewer.getTextWidget();
+								if (styledText == null) { // fSourceViewer is disposed
+									return Status.OK_STATUS;
+								}
 								Point selection = null;
 								// keep scrolling state in details pane in case
 								// of longer string over multiple lines