A fast way to get a better overview in the viewports is to toggle the visibility of nodes by category - SHIFT+S for shapes, SHIFT+L for lights and so on. But you change the selection if you have nodes of this category selected because they get deselected.
This may be wanted for filtering your selection, but is bad in other situations like when animating a character that has many many shapes that block the clear view on your animated character but are needed to control the rig. As an animator you usally want to keep the selected shapes when toggling the shapes-category. So the best way would be to have the choice per category wether you want to keep the selection or filter it.
