Fix Minor issues with favorite menu and others

This started with my facing https://github.com/linuxmint/mintmenu/issues/45 and its connected forum post, and the lack of any response in either forum. 

I fixed that and a few other minor issues (not sure if right way but they seem so in most cases)

A few are left
- Type something + Click search - text lost  - This is because of modification to focusSearchEntry function
- Type something + click favorite - first click clears the search, second does the toggle - not sure

Much of what I fixed have resulted from 2 commit earlier this year, https://github.com/linuxmint/mintmenu/commit/84aa87727f6341a441fb1e5cb32e3bbe857e44a5 for the first unresolved issue, https://github.com/linuxmint/mintmenu/commit/8812475eac9b267ecead6a92cc1708035c88d086 for all the focus issues, as ironic as that is..