Hum, after some fiddling around, I realised this was caused by an interactive Python window (i.e. this kind of stuff, Python Interactive window ). Simply closing the window and restarting Cursor did the trick.
Note that I’m using interactive windows because Cursor’s Jupyter Notebooks’ Support is utterly disastrous, at best, as reported in Inconsistent Jupyter notebook handling - #2 by edervieux , Changes at the bottom of a cell in Jupyter Notebooks cannot be seen, and Highlight in scroll bar does not work in notebooks - #2, among other places…