Tray icon is non-transparent on some Linux desktop environments

[crschnick]

I have tested my application xpipe on various Linux distros and noticed that the tray icon it looks off on some of them. Here is for example how it looks on manjaro with Plasma and KWin (the default Manjaro ones):

On any other operating system or DEs like gnome it looks fine.

For reference, this is the code I use to call FXTrayIcon: https://github.com/xpipe-io/xpipex/blob/d2ac3383ac0b6202f567f42b963819f10b0c98c8/app/src/main/java/io/xpipe/app/core/AppTray.java