After starting geany 1.37.1 Debian GNU/Linux 10 (buster) with a markdown-file that was opened already yesterday, the preview is not working (see below) until the moment I edit the file again. Phew, quite difficult to explain exactly, sorry.
The shown 'error' in the preview is: _The current document does not have a Markdown filetype_
Not a big issue for me but I still wanted to post it