Crash 'Fatal Exception: java.util.ConcurrentModificationException'

[usmanrana07]

Sometimes app crashes on 3D dialog, crash logs are as following:

Fatal Exception: java.util.ConcurrentModificationException
       at java.util.HashMap$HashIterator.nextEntry(HashMap.java:851)
       at java.util.HashMap$KeyIterator.next(HashMap.java:885)
       at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1415)
       at android.view.ViewRootImpl.handleDragEvent(ViewRootImpl.java:6258)
       at android.view.ViewRootImpl.-wrap11(ViewRootImpl.java)
       at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:4160)
       at android.os.Handler.dispatchMessage(Handler.java:102)
       at android.os.Looper.loop(Looper.java:154)
       at android.app.ActivityThread.main(ActivityThread.java:6682)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)