BCGControlBar Pro for MFC
BOOL CBCGPRibbonCaptionMDITabsOptions::m_bTabCustomTooltips

Specifies whether custom tooltips are enabled or not.

If this member is TRUE, the BCGM_ON_GET_TAB_TOOLTIP message will be sent to main frame. You can handle this message and provide the framework with custom tooltips to be displayed for MDI tabs.