Nesting Toolbar Menus causes Vassal to lock up

Nesting toolbar windows like this:

Main Map
. |
. ±–> Card Decks (Toolbar menu)
. |
. ±----> Card Deck Category 1 (Toolbar menu)
. |
. ±------>Subcategory 1 (Toolbar menu)
. |
. ±------------------------------------+
. | |
. Card Deck 1’s Map Window Card Deck 2’s Map Window

causes Vassal to freeze when you click on the nested toolbar menus to bring up the lowest level Map Windows (the program freezes before the Map Window names are displayed).

Module included to demonstrate the issue.
Start the module and click on the “Card Decks” toolbar button then work your way down. The program freezes on my computer before the final Map Window names are displayed as menu choices.

Bah, the forum won’t display the spaces in my diagram. Oh well. The module reproduces the error, at least on my computer.

Bug [2806188]: Nesting Toolbar Menus causes Vassal to freeze