I have seen in 2015 that sometimes when I open a part, all of the sketches will be visible.

when I go to the hide and show items pull down, the sketches button is active.

when I turn it off, the sketches close, as they should but why would that button become active and all of the sketches become visible when I open a part. Is there a setting that opens all sketches when a part is opened?

Again, this is intermittent behavior.

As a side note we have seen this when downloading Mcmaster Carr parts. And I should note that the parts I am seeing this on are not modified Mcmaster parts.