Applications can't set selections

[ouroumov]

@robwlakes

Another is when I try to save a new homepage for Firefox, it keeps on falling back to the installation default.

This is a bug affecting 16.10 and later versions that's likely unrelated to the other issue you're experiencing:

Ubuntu MATE always forces search start page in Firefox

I am huge fan of both Ubuntu Mate and Firefox, but rather frustrated with U-Mate changing my e-mail ‘home-page’ to a ubuntu search page. What do I have to GIVE UP? MATE or FIREFOX???