I laboriously entered signal labels onto wires that would be my source signals. When I added the source and destination arrows, those signals disappeared.
So I laboriously re-entered the signal labels.
I decided I wanted to change the layout for graphic clarity. (so they would be horizontal instead of vertical) I can't move the destination arrows. If I delete the wire it is on "POOF" all my data goes away.
So I did my graphical changes, deleted all the arrows, redid the arrows, laboriously re-entered the signal labels...