I've been chasing a bug for some days now, and wonder if anybody has an idea what could be wrong.
It works most of the time, see attachment (no source yet, it's confused and huge). But sometimes I see that only a small 20x20 square in the upper left corner is being painted (correctly btw).
Size of the controls is OK, size of the two bitmaps involved is OK, too - checked with e.g.
invoke GetObject, APs.apBitmap, BITMAP, addr info
invoke GetObject, APs.apBitmap2, BITMAP, addr info
invoke GetClientRect, hCtrl, addr rc
GdiPlus calls do not report errors, Gdi calls are fine, too.
No significant leak (if any).
No heap corruption.
No crashes under the hood.
Sometimes the mouse cursor turns into a black square the same size as the painted little square.
The six controls have WS_THICKFRAME, sizing them has no effect. But when sizing the main window, it frequently starts working properly!
Has anybody seen something similar?