Thread: MessageBox de-maximizes window

If I use MessageBox() to create a simple message box for my window (to be specific a Dialog Box), if it is maximized, MessageBox will de-maximize (restore to its original size) the window. I'm not sure if this is the intended behaviour, but is there anyway to prevent this?

Meaning I could respond to a WM_SIZE message and stop it from de-maximizing?... I tried this, and it works well in forcing the window to re-maximize (although when the MessageBox pops up you can still see it quickly restoring then maximizing again in the background instead of maintaining its maximized state as would have been nice), unfortunately though, there's no real way of distinguishing between when the user is intentionally de-maximizing the window or when the message box is (SC_RESTORE is one indicator, however I quickly found out there are other user-initiated ways of restoring a window without SC_RESTORE's involvement, i.e. double-clicking the caption bar).
I've checked my application again, and this appears to be happening with any form of pop-up (i.e. if I launch another dialog box from it, it will de-maximize the window as well). Maybe this is because the window I am using was created by DialogBox, or am I just doing/returning something wrong?
I could go through all the work to transform my Dialog Box into a registered window and use CreateWindow instead, though I would still think it odd that DialogBoxes should be de-maximized by default when pop-ups occur from them...

here is a copy of my application (does not contain all files, just the .exe). To see what is happening, click "yes" to the first prompt to bring you to the window entitled "Setup", and then maximize it. Once maximized, click any of the first 4 buttons, or the Close button. Any of these will launch a pop-up/dialog box which will promptly de-maximize the window.



Link removed by moderator. Sorry. Policy is to supply the source, not the executable.
Cornedbee

I've just tried a sample simple window demo and it turns it that this did not occur with a registered window, which leads me to believe more now that this is an issue with Dialog Boxes only. Furthermore, I've noticed now that this occurs even when switching windows (i.e. alt-tabbing out of the dialog box also de-maximizes it). I have no idea what is causing this. My dialog box is defined as so in my resource file:

Code:

IDD_DIALOG DIALOGEX DISCARDABLE 5, 0, 0, 0
STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENU | DS_SHELLFONT | WS_MINIMIZEBOX
CAPTION "Setup"
FONT 8, "MS Shell Dlg"
{
}

and has the following styles added to it during run-time:

Code:

 WS_SIZEBOX | WS_MAXIMIZEBOX