I’m trying to get Ajax Search Pro to accept document mime types (PDF, DOCX and PPTX, specifically), but every time I enter them as a comma separated values (with values taken from the mime type table), per instructions, and save the search it defaults back to just the images.
I am not really interested in searching the content for these files, just the title and description in the media library.
I logged in, try to add them, and it works on my end: https://i.imgur.com/LwoGG3m.png
Check if you have any browser extensions active, which may change/alter contents of text inputs – like form fills and similar. From the plugin side it works all right, so it is very likely the browser causing the problem.