On Ubuntu 16.04 release 1.27 (not tested on latest 1.33 by me) when editing an HTML file, and deleting the last letter of a HTML tag, Geany crashes. The window disappears. Your edits are not saved. Recent file list is not saved. How to duplicate is below
<p> paragraph text here </p>
Position the mouse cursor after the p in the tag <p>, and press backspace.
That easy.
I imagine it has to do with syntax highlighting, and it fails to find a 'tag' value for the HTML Start Tag, that "used to exist". I did not turn off syntax highlighting to find out.
I did search GitHub for a similar issue report, but the keywords I used (two sets) found none.