The javax/swing/JMenuItem/6458123/ManualBug6458123.java test is closed-source, it exposed a problem reported in JDK-8373650 which proved to be a regression of JDK-8348760.

I did run the ManualBug6458123.java test while I was testing changes for JDK-8348760, especially for backports. I probably would have noticed the problem in JDK-8373650, but I may have been distracted at the time, so I didn't report it myself.

The javax/swing/JMenuItem/6458123/ManualBug6458123.java test can be open-sourced, but it needs cleaning up.