[TEST_BUG] java/awt/Mouse/EnterExitEvents/DragWindowTest.java failed on ubuntu 13 and mac 10.11

regression test java/awt/Mouse/EnterExitEvents/DragWindowTest.java failed on ubuntu 13; it passed on oel 5.7 and ubuntu 12
tested with jdk's: 8b103, 8b57, 7u25b15 - failed with all

failure log:
----------System.out:(0/0)----------
----------System.err:(13/771)----------
java.lang.RuntimeException: No MouseEntered event on Drag Window!
at DragWindowTest.main(DragWindowTest.java:85)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.sun.javatest.regtest.MainWrapper$MainThread.run(MainWrapper.java:96)
at java.lang.Thread.run(Thread.java:724)