Can't delete a global guide

I’ve discovered a global guide in my font and can’t delete it. When I select the guide and press Backspace, nothing happens. I’ve tried to delete it from every glyph in the font with no success. Any ideas how to delete it? Thanks

Is the guideline locked? (i.e. does it have a lock icon?) If that’s the case, you need to unlock it first, from the context menu.

This is one of those old bugs that comes and goes with updates. I can always delete the stuck guides after quitting and restarting Glyphs.

For some reason today I was able to delete the guide without any difficulties. Thanks for help!