Once a project gets up to a moderate level of complexity it starts happening.
PLugins lose some of their GUI components. With high quality plugs like UAD it actually looks like something fell off, exposing the panel beneath. T-Racks Limiter just has a blank look.
The most annoying case is the Line6 PodFarm, which shows just an empty window frame, making it completely inaccessible.
Any rhyme or reason to why / what / when etc etc ?
I have 5.5.3 - are things any better in 6?