I have had the problem where after I sneeze, or wink/blink my eye is stays extra droopy afterwards and doesn't open as fast.. and when my symptoms exacerbate I must have incomplete closure, especially at night too..
Veronika- curtain closing sensation with your eyes can be a sign of other problems too, if it's not your actual eyelid closing that appears like the curtain- . retina problems I believe (can't remember exactly).. unless your talking about your actual eyelid closing, I would mention it to your dr.. but I can imagine your sick of testing/dr's appointments, however it might be as simple as seeing an opthamologist for one visit?