I suspect this might be a problem with the editor module, but I think the issue should be raised here.
I'm using geany: on Slackware64-current Linux, geany 1.38 (built on 2021-11-23 with GTK 3.24.29, GLib 2.68.2) I configged the editor fron as 'Bitstream Vera Sans Mono Roman' at 11 points.
At this scale, underscores are not renderered.
When I scale the font up or down, using ctrl-- or ctl-+, the underscore reappears. Of course I could probably change the font, but I have had some problems with other mono-spaced fonts which have unicode-characters defined correctly (apart from taste issues)
I have the impression that this might have appeared on upgrading to 1.38. I can't remember if I ever noticed this before.
John
Closed #3038.
Fixed in master
Duplicate of #2466 which has been re-pinned until next release.
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