Comment 4 for bug 1133676

This is actually a feature, not to make the windows to resize when highlighted (since they show the real-sized decoration only on mouse over).
Design mockups respect this behavior in fact, see: http://ubuntuone.com/7B8ot1UA2gPKm9q8F0K198 [1]

[1] Taken from http://design.canonical.com/2012/03/task-switching-in-ubuntu-and-a-introduction-to-the-spread/