No, it is not a bug. It is probably due the application uses a menu created by Interface. When Interface creates a new, it gives to the accessory items in the menu the following names : Accessory 1, Accessory 2, ... Unfortunately, EvntWindom() - which handles automatically the menu shortcuts - interpretes the words 1, 2, 3 of accessory items as shortcut. It is why there are not interpreted as keybord event but as menu event. The solution is to give an another name to this accessory items. For example, Accessory_1. (Thanx to Zerkman for the solution).
You have to bind the WM_PREREDRAW event instead of the WM_REDRAW event. You should remove the standard redraw function binded to WM_REDRAW (with EventDelete()).