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  1. JDK
  2. JDK-8133859

[macosx] Autoscroll continue to run due to failed drag and drop operation leading to an unstable application

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    • x86
    • os_x

      FULL PRODUCT VERSION :


      ADDITIONAL OS VERSION INFORMATION :
      Mac OS X 10.9.5

      A DESCRIPTION OF THE PROBLEM :
      Very intermittently (perhaps once a fortnight in an app which is used heavily throughout the day) a drag and drop operation won't cancel properly and the system is left with an autoscroller running even though the mouse has been released, the window has been deactivated and reactivated, and so on. Moving the mouse (with the button released) causes the window to scroll wildly and makes the application unusable until it is quit and relaunched.

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      It's very difficult to reproduce because it is so intermittent. Currently I'm using /Library/Java/JavaVirtualMachines/jdk1.7.0_60.jdk/Contents/Home from within Eclipse. I realise that's not the latest version but I have seen this issue across different JVM versions and this is the first time I have been lucky enough to catch it while in a debugging session. I can only suggest you do some code inspection rather than holding out for a repeatable test case as by its nature I don't have one I'm afraid.


      ERROR MESSAGES/STACK TRACES THAT OCCUR :
      No obvious exceptions etc in log file

      REPRODUCIBILITY :
      This bug can be reproduced occasionally.

      ---------- BEGIN SOURCE ----------
      Analysing the application while in this broken state I have a java.awt.dnd.DropTarget$DropTargetAutoScroller with an active autoscroll timer that keeps firing, but where component.dropTarger.autoScroller is null.

      Looking at the code this could happen if DropTarget.dragEnter() is called twice in succession without dragExit() being called. When dragExit() is then called that would cancel the second auto scroller but leave the first one running.
      ---------- END SOURCE ----------

            pardesha Pardeep Sharma
            webbuggrp Webbug Group
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              Created:
              Updated:
              Resolved: