Suggestion: clear visual indicator of the tops and bottoms of docking ports

[kdaviper]

It would be very handy to have some sort of in-vab graphic to clearly show the tops and bottoms of the docking ports.

Perhaps the bottoms could have a red "X" on them.

I thought I had encountered the docking port bug, but it turns out one was upside-down. 

Yes I know they do look different from either side but I still managed to screw it up though I thought I had double checked in the vab.

I think this would be appreciated by everybody, from first-timers to veteran kerbonauts.

[DaveLChgo]

In this case I think it better to state you would like to know the front versus the back.  As there is also a top and bottom.  I believe it is marked by a yellow arrow.

Mixing up the front and back?  Happened maybe once or twice way way back when a very long time ago.   Something that may help.  Pressing the space bar while the part is selected will reset the part back to its default orientation (front up if in VAB).