On Thursday 11 December 2003 22:45, Dimitrie O. Paun wrote: > On December 11, 2003 04:32 pm, Andrew de Quincey wrote: > > I have concluded that the WM_ERASEBKGND is sent from within WM_PAINT when > > the toolbar detects that the mouse has moved off a button and wants to > > de-highlight it. > > Well, it probably does a InvalidateRect() call. You can try an ugly > InvaldateRect(hwnd, 0, TRUE); > but this will probably result in flicker. For added bonus, figure out > the button's rect, and pass it in: > > /* figure out stuff in rect */ > InvalidateRect(hwnd, &rect, TRUE);
Actually, that code is almost already in there... it does call InvalidateRect() already, but passes FALSE because TOOLBAR_HasText() returns false. This happens in the TOOLBAR_MouseMove() function. Originally, I had decided that this wasn't what windows does because in spyxx, the WM_ERASEBKGND occurs AFTER the WM_PAINT. However, I now see I have misread MSDN: The call to BeginPaint() inside the WM_PAINT issues the WM_ERASEBKGND because bErase was TRUE, so it would obviously occur after the WM_PAINT. This sounds much nicer. > BTW, what are the parameters of WM_ERASEBKGND? wParam == device context handle lParam == unused
