BCGControlBar Pro for MFC
UINT BCGM_CUSTOMIZETOOLBAR

The BCGM_CUSTOMIZETOOLBAR message is sent by CBCGPToolbarCustomize to notify the parent frame, that the customization dialog was created (start customization) or destroyed (end customization).

Parameters
wParamTRUE if customization is started, FALSE if customization is finished.
lParamThis parameter is not used.
Returns
should return zero.

Process this message to take additional actions upon customization start and finish.