Just looked what we do there. It's using a
wxMessageDialog which should "know" the correct size. Additionally, the dialog may be centered on the main window (if you have enabled the smart placing feature), which again only calls the standard wxWidgets
CentreOnWindow function under all non-Windows platforms.
The only time the dialog's size can modified at all is if you have enabled the smart placement functionality in constraint mode, and if your screen is so small that the dialog would not fit. However, you
cannot even do that any more, since someone removed this option from the settings panel
So... clueless as to what happens there with you.