On Windows, with common messages boxes, you can just do Ctrl+C for copy and you get the message box text in the clipboard.

Don't know if that helps you particularly, but it is great when it works and little-known.

Thanks, doesn't help me, but you're right, a good tip to know. Though I'd still prefer a similar option to start selection directly in the UI instead of finishing the job in a text editor, this would also help highlight text in a screenshot without having to do image post-processing! I'd even accept some arcane finger-breaking ctrl-alt-win-x-y-z (which I could rebind) for the privilege

All the more annoying when such years-old fundamentals are broken in all the new "supposedly better" frameworks

I’ve never done it twice, I can tell you that much!