BCGControlBar Pro for MFC
static void CBCGPKeyboardManager::AllowPrintableCharacters ( BOOL  bAllow = TRUE)

Enables or disables assigning printable characters to the keyboard accelerators

bAllowIf this parameter is TRUE, assigning printable characters is allowed.

By default, user can use any character such as 'a' and, if your view is a text editor, typing 'a' character is not possible anymore (command associated with 'a' will be executed instead). You can prevent this by calling AllowPrintableCharacters() static function with parameter FALSE.