@Override
 public void disconnect(IDocument document) {
   if (document instanceof DisassemblyDocument) {
     final IBreakpointManager bpMgr = DebugPlugin.getDefault().getBreakpointManager();
     bpMgr.removeBreakpointListener(this);
     document.removeDocumentListener(this);
     fCatchup = null;
   }
   super.disconnect(document);
 }
 @Override
 public void connect(IDocument document) {
   super.connect(document);
   if (document instanceof DisassemblyDocument) {
     final IBreakpointManager bpMgr = DebugPlugin.getDefault().getBreakpointManager();
     addBreakpoints(bpMgr.getBreakpoints());
     bpMgr.addBreakpointListener(this);
     document.addDocumentListener(this);
   }
 }