Test +javax/swing/JPopupMenu/4870644/bug4870644.java fails on Ubuntu 18.04 LTS with following error message

java.lang.RuntimeException: java.lang.RuntimeException: Default button reacted on "ctrl ENTER" while menu is active.
at bug4870644.main(bug4870644.java:95)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:835)
Caused by: java.lang.RuntimeException: Default button reacted on "ctrl ENTER" while menu is active.
at bug4870644.<init>(bug4870644.java:159)
at bug4870644.main(bug4870644.java:92)
... 6 more

JavaTest Message: Test threw exception: java.lang.RuntimeException: java.lang.RuntimeException: Default button reacted on "ctrl ENTER" while menu is active.
JavaTest Message: shutting down test