Hi Bridger,
Glad that helped. I find myself working with Unix-like OS most of the time, and I'm very accustomed to the XWindows "use the middle mouse button to copy highlighted selection" behavior. I've noticed that some applications don't support this behavior - BaseX GUI is one of them - and I think the commonality is Java... Swing (? at least as I type this I think that Swing is the commonality).
True, the middle mouse button for copying and pasting text is not supported by Swing, probably because this feature is specific to Unix-like OS. We have added support for it in the text areas, though, no matter which OS is used. Does this work on your system?
The BaseX text area component has been written by ourselves, as the standard JTextArea components cannot process and highlight long texts efficiently. I think we could try to extend the standard Swing components (JTextField, etc.) to also support the middle mouse button; would that be helpful?
Best, Christian