Is there a place to enter screen resolution for a new portal?

I looked though Host and couldn't see one.  When I go into one of the pages with data entry on it, I have a horizontal scroll bar.  There is a little stuff to the far right.

Is it because the page had stuff placed too far to the right or is there a setting where we can enter the company default of 1024X768?

Thanks Sebastian

Then I am not sure how I can see a horiz scroll bar on two of our existing (takeover) apps unless the width is fixed and the programmer placed content beyond the right side.  I'll have to look more into it.  Thanks for pinpointing the skins for me.