Get when a window is disabled

[jacdelad]

Hello,
for my ribbon I need to know when the window, where the canvas is put on, is getting disabled (via DisableWindow). Do I receive a message or how can I get the info that it got disabled? Not searching for the API "IsWindowEnabled", because I would have to call it periodically which I don't want to.

[jacdelad]

Ahaaa,
I found out, that firstly #WM_ACTIVATE and a callback is what I'm searching for and secondly PB already sends a #PB_Event_LostFocus, when the window is deactivated; I just have to additionally check whether the window is active or not. Case closed.