I have quite a few on my round but to be honest they never cause me a problem.
First clean you have to just rinse and rinse and rinse all the dirt out of the frames and in particular the middle channel.
Then as Sean says leave the top panes to drip out, and then clean the lower pane.
After that I just make sure to not put too much water above the top openers and they come out fine.
If it's two top openers and a big pane underneath, then I make sure to avoid putting water in the middle channel between the two openers, as 9 times out of 10 this is what causes run downs.