LazPaint reveals many window size edge cases

[canadaduane]

I installed the lazpaint-gtk2 package and discovered several interesting edge cases that the compositor does not seem to be handling well:

1. On initial load of LazPaint, a very small (80x80) black and gray window appears. I believe this is intended by the app author to be a splash screen window. Because it is so small, no window UI buttons are visible. If manually drag-expanded before it finishes loading the main app, the splash window does not appear to show the LazPaint logo. (I would expect the splash window, not a small gray window).
2. Once the splash screen disappears, an app window appears that is not reasonably sized. (I would expect a large windowed app).
3. When using the app, if you get to the open file dialog to load an image, the main app window disappears, and a small version of the app's built-in file open dialog window appears. (I would expect the app window to remain while the file dialog appears over top).

Splash screen window:

Initial app window:

Full screen app (correct):

Full screen app, while file dialog window is open (app disappears):

Note: the lazpaint-qt5 package seems to circumvent the above reported issues, and behaves mostly correctly, except for point 3--the main window still disappears during file selection dialog.