One that got me recently was that there is no LayoutTransform property (although there is a RenderTransform property). Therefore, you cannot apply a transform and have the adjacent elements respect the 'new space requirements' of the control, which will then cause it to overlap with other elements or have blank space.
This was a problem for me because I wanted the scrollable area inside of a scroll viewer to change with the transforms. I was able to get around it, but the process would be much more difficult if you were trying to rotate or do another transform.
