[Laffs]

Same sort of problem I had with the effects window to expand up not down.. In the end the only way I could get it to do it was... this

Make the page the size it is going to be at its full extent
Then set whats visible and set pack location to the right
And on mouse over its a case of setting show/hide or even swaping the locations of the other pages and changing background/frame size
But the parent size stays the same all the time just you cant see it

Any of that make sense lol