Gorm and PopUp buttons on Gnome

[A. Arias]

I'm having an odd issue on Gnome with Gorm and PopUp buttons. Steps to
reproduce it:

1) Open Gorm and make a new app.
2) Add a popup button to the window.
3) Add items to the popup button.
4) Add any other element to the window, for example a button.
5) Try to add more items to the popup button. I'm unable to open the
popup button with a doble click to add more items.

One solution I found is, after double click the popup button, select the
gorm document window. This show the popup button correctly. But this
isn't intuitive. On WindowMaker I don't have this problem.