Check if fileMDT doesn't exist first

Performing comparison when it doesn't is an error. Just swap aruments.
No longer dealing with opening thru display

We are no longer setting display block here, this is now done once we
have injected the DOM elems into the tree at that dir. Once that is
done, we set the display to block. We still set none here when
collapsing. This avoids a flash of possibly unsorted files.