Liftgate open warning light/bell/something

So, twice now have I broken the back liftgate window because it was up when I drove, unknowingly, through the low opening Condo garage door.

Any suggestions as to a warning bell or flashing light that I could install so I WON'T do this again ?!! Is there a warning light all ready installed ??????

I think what happens is that when I get into the drivers seat to drive away, my knee touches the liftgate button.

Maybe even put a sticker on the front window to remind me to look, or SOMETHING, PLEASE !!