style.horizontally_stretchable screwing things up?

[Therenas]

Hi there, I have a small GUI problem I would like to adress. It concerns scroll-panes, and I want the scrollbar (if it is visible) to always be as right in it's 'container' as it can be. The property 'horizontally_stretchable' on the scroll-pane seems to do this just fine, but I found that it screws up other parts of the layout. Seems like it influences padding, alignment, and possibly others? Can't really figure it all out so I'm not able to fix it. Does anyone have any advice on this? Or a different solution to have the scrollbar right-aligned would be great too.

Here is a picture of what I don't want (left, without the stretchable flag set) and what I want to achieve (right) without the side effects.