--- misc/rhino1_5R5/toolsrc/org/mozilla/javascript/tools/debugger/Main.java	Wed Feb 23 10:25:09 2011
+++ misc/build/rhino1_5R5/toolsrc/org/mozilla/javascript/tools/debugger/Main.java	Wed Feb 23 10:25:01 2011
@@ -1045,9 +1045,18 @@
             } );
     }
 
+    // Fix taken from <ftp://ftp.mozilla.org/pub/mozilla.org/js/rhino1_7R2.zip>
+    // toolsrc/org/mozilla/javascript/tools/debugger/SwingGui.java:
     private void updateToolTip() {
-        // in case fileName is very long, try to set tool tip on frame
-        Component c = getComponent(1);
+        // Try to set tool tip on frame. On Mac OS X 10.5,
+        // the number of components is different, so try to be safe.
+        int n = getComponentCount() - 1;
+        if (n > 1) {
+            n = 1;
+        } else if (n < 0) {
+            return;
+        }
+        Component c = getComponent(n);
         // this will work at least for Metal L&F
         if (c != null && c instanceof JComponent) {
             ((JComponent)c).setToolTipText(getUrl());