Thank you for for using Multi Find and for your feedback: I am glad to hear that this extension has been helpful for your academic work.
To answer your concerns:
- Unfortunately, regarding the support of PDF, I am afraid this is too complex for this extension (basically I would have to re-write a PDF-viewer). A possible workaround is to convert the PDF into an HTML page.
- I understand the standard selection white highlight masking the extension colored highlight can be disturbing, but it is important to distinguish the current selected word while jumping from one occurrence to the next one, in case several of them are on the same line, for instance.
- And I appreciate your suggestion of the broader search with a random middle part: I will certainly consider implementing a joker/wildcard character in the future.
Thank you again for your support, and please keep checking for updates!

Edit: with the version 1.40 (Oct. 13), you can now activate the soft glow highlights: the color of the highlighs should still be visible even if you select the text.