[Bug]: Splash screen does not have transparency on Linux

[kwvanderlinde]

Describe the Bug

When the splash screen opens on Linux, it has opaque white edges. On Windows, the edges are transparent with a nice fade.

This is not new. I don't think I've ever seen a transparent splash on Linux. In fact I was shocked when I first ran MT under Windows and saw the transparency.

To Reproduce

1. Open MapTool on Linux
2. Watch for the splash screen to open with it's hard edges and white border.

Expected Behaviour

The dialog should have transparent edges. Or if there are cases where it cannot be transparet, the edges should be black to better meld with the image.

Screenshots

On Linux:

On Windows:

MapTool Info

1.14.3

Desktop

Linux Mint 21.3

Additional Context

No response