As I wrote, resizing and relocating the scrollable containers is a touchy subject which should be handled with caution. Personally, unless it is absolutely required, I avoid changing their size and am extremely careful with relocation as well, knowing that I got myself into a predicament that was not fixable after a while, unless I used the 'Undo' button many-many times, losing other changes I did along the way.
"Your mileage may vary", of course 
As for the Step * error, in case you do have cached tabs, I'd bet it won't happen anymore if you turned off tab caching. At least that's my experience... try to experiment and see what happens.
Regarding pressing the buttons via a script: are those buttons hidden by any chance?
If they are, then this MAY be the effect of the latest Personas client from the 9th of October which is known to have an issue with hidden objects.