I have 2 issues and any help would be appreciated...

1) How do I get muPDF to work? I'm using Debian Wheezy and muPDF does not appear in the any of the Application menus. It does appear when I right-click on a PDF document but nothing happens and CPU usage is flat. I uninstalled and reinstalled muPDF using apt-get but that made no difference. I installed xpdf and that works perfectly... but may be slower than muPDF hence my interest to get that working.

2) How do I stop the Gimp from opening when I double-click on a PDF?

Thanks in advance for any suggestions.