Wrong combo selected on right click (Bottle Shop Types)

Steps to recreate:

1. File->New
2. Quest->Misc Data->Bottle Shop Types
3. Click 'Edit'
4. lclick red potion icon
5. rclick red potion (combo #5120)
6. Observe combo #5253 is selected

The Bottle Shop Types window is created by onBottleShopTypes() in zquest.cpp

Cannot reproduce this by right-clicking the combo list, selecting "Open Combo Page" and proceeding from step 5.

The Select Combo window is created by draw_combo_list_window() in zq_tiles.cpp