v4: - remove '`first_window` pre-check; - add patches to fix another regressive aspect of commit 8d7de32cd646f3d1f118836e643e6146c9837278 (also reproduced with the app from Bug 59034 after the initial fix). Message box dialog has flags "compatible" with startup info. I think the added dialog test clearly distinguishes between the potential handling of the hidden (or minimized) window while showing message box (with, e. g., some message handling or another window show on the way, how that happens with Wine from DIALOG_DoDialogBox, while that doesn't work reliably) and some explicit disablement of startup info effect in the MessageBox. In the test the dialog window is not even created (due to handling in the hook) while the startup info doesn't have an effect after that, suggesting that is explicitly cleared during MessageBox processing but before hitting any window procedures. While doing the same with DialogBoxIndirect doesn't have that behaviour, suggesting that is specific to MessageBox and not (modal) dialogs in genera l.