4.2.16 loses screen, cursor control

[gpaCook]

I didn't see any existing topic addressing this, so:
vbox on OSX Mountain Lion, Ubuntu Studio guest.

Everything fine on 4.2.12, 4.2.14. I installed 4.2.16 and experienced the following:
- Guest window would resize in scale or non-scale as before, but contents remained original size (Ubuntu screen stayed small, tho guest screen would stretch).
- Cursor behavior was incorrect. Cursor had to be clicked to appear when moving between guest and host, regardless of the mouse integration mode. And cursor position did not correspond between the two.

I did install guest additions and extensions.

I went back to 4.2.14, and things are good (I notice my guest additions are still 4.2.16, but things still work fine).

Not sure if bug or user error, but wanted to share asap incase others encounter, and if solved.

Thanks,

[mpack]

Please post observations about 4.2.16 in the 4.2.16 discussion thread.