activity.loadlayout question

When I do an activity.loadlayout() in a sub, does this load a new instance of the layout each time that sub is called? Or does the routine know it is already loaded and just make the current layout active. I'm still trying to understand memory usage in b4a and the best ways to handle it.

Currently, I use panels for most layouts and simply set them to visible or not and sendtoback or bringtofront.

Thanks,

--- Jem