BCGCBPRODLLEXPORT UINT BCGM_ON_SELECT_UNDO_ACTIONS

The message is sent to the main application frame when the user selects some undo actions from the drop-down list.

Add the BCGM_ON_BEFORE_SHOW_UNDO_ACTIONS_LIST registered message handler to the toolbar owner class (e.g., CMainFrame), obtain the number of selected undo actions by calling the CBCGPToolbarUndoButton::GetSelectedActions method, and execute the selected undo/redo actions (specific to your code).

Parameters

wParam	contains the toolbar undo button command ID.
lParam	a pointer to the CBCGPToolbarUndoButton object.

Returns

non-zero to prevent the undo button's drop-down list from closing.