When working with a busy model it is often difficult to select the right object/element. Tabbing through the available selection candidates sometimes doesn't work and it takes a bit of zooming in and out to finally get at the right thing.
Other times we have some objects whose shape and position has been set and locked and they won't change. Selecting those elements doesn't make sense most of the time.
It would be really helpful if there was a way to disable selection of locked items. This of course would be a toggle option of the selection process.