REG: Menu does not disappear when clicked, keeping Choice's drop-down open, XToolkit

I have some components added to a ScrollPane and Scrollpane is added to a frame. Frame has a menubar with few menus added to it. I am clicking on Choice and the drop-down opens up. Keeping the drop-down open, I am clicking in the 'file' menu in the menubar. Menu also opens up. But after this, Menu just stays there for ever and does not disappear. I tried clicking on all the components and moved the frame to a diff location but menu just stayed there where it was opened. This looks pretty bad.

This is reproducible only with XToolkit and not on Win32. This is not reproducible on Mustang-b36 but reproducible on Mustang-b42. Hence it is a regression introduced inbetween b36-b42. I reproduced it on Cinnabar as well as SolSparc10-JDS. Fix needed for RC.

Run the attached test. Click on Choice and drop-down will open up. Keeping the drop-down open, click on the menu. After that, click anywhere else, move the window etc but menu will still stay there.