Fix some duplicated menu items

A function used to get called once that now gets called multiple times. Independent of that, some lists randomly contain a large number of duplicates. (Probably an artifact of the decompilation process.)

Work around another Mono bug

Rare NPE when figuring out alignment of text on Linux.

Fixes a Mono interop issue

You wouldn't notice the difference on Windows but I do on Linux.

"Works on my PC"

Tested locally. Appears to work.

Be sure to back up regularly anyways.