I don’t know if this was discussed before, but with the addition of the MathJax preview feature (which is nice; great work @hengiesel !), we’ve lost the ability to copy expressions like before.
True, I’ll take a look into that.
As a work-around for now, you can copy/paste from the HTML editor.
Looking into this some more, I realized this is actually a bug on Windows. It does work on macOS.
Can you also confirm that this is in fact a Qt6 issue? I think it’s because clipboard.dataChanged does not fire in Qt6 on Windows, which means the internal flag is never set. That also explains why the Mathjax image is stripped: it’s treated as an external image.
It’s a Qt6 issue, apparently. I can’t reproduce it in the Qt5 build.
This ticket in Qt’s bug tracker looks related: [COIN-830] QClipboard::dataChanged() was not emitted in QtWebEngine context - Qt Bug Tracker