FULL PRODUCT VERSION :
1.8.0_144-b01

ADDITIONAL OS VERSION INFORMATION :
16.7.0 Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64 x86_64

A DESCRIPTION OF THE PROBLEM :
Two-finger click (a right click) on a mac touch pad will show a popup menu, but then the menu is almost immediately closed. From debugging, this because a mouse scroll event reaches the component that was clicked on and BasicPopupMenuUI.MouseGragger calls cancelPopupMenu on any mouse_wheel event that is outside the popup.

The mouse wheel event comes in when you wiggle or lift you fingers after clicking. This is almost impossible not to do.

I found a matching report in bug 8180737 which was marked as cannot reproduce, but it is reproducible.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
See http://bugs.java.com/bugdatabase/view_bug.do?bug_id=8180737 a linked video of the problem.

Any swing JPopupMenu (netbeans works as a testcase). Two-finger click on anything in the project window and see the popup hide as soon as you lift your fingers.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Popup stays open.
ACTUAL -
Popup closes 90% of the time.

REPRODUCIBILITY :
This bug can be reproduced often.