Do get non-visible UI elements actually rendered?

Christoph Mann's icon

Hello guys,

if I have some graphical elements inside a patcher( lcd, scope~, or jitter objs ): Do they constrain CPU even if not visible onscreen (e.g. inside a subpatcher)?
The UI toolkit should be clever enough not to render anything invisible, but the model logic will be updated anyways, I thought. At least using jitter, embedding a big pwindow/jit.noise did not lower CPU usage in any way (as was to be expected).

How is this handled in Max and MSP UI objs?
Greetings,
Christoph