Electric Windows - will not shut fully. Sensors?

[Bobcat]

Hi,
Just found the front passenger window open about 3"...off course it's raining! It will not shut fully, goes up, then back down by itself, as if it senses an obstruction. Checked the channel, and it seems to be clear. Had the windows open a while yesterday... fancied a bit of wind in the hair (although more wind than hair). Closed them last night, using the key fob (good trick). Anyone got any ideas, it is almost shut now, auto close on button, and press button momentarily close to the top... still raining though...

A4 Avant 3.0tdi Quattro

Regards Bobcat.

[Bobcat]

Hi,
Stopped raining... so ran a blunt terminal screwdriver round channel, expecting to find a dead bug or debris, but found nothing. Repeated with a small, stiff paintbrush, still nothing I could see, but the window now closes normally. Must have been something very small. Anyone know if sensing is by motor load/current drawn, or actual sensor in the channels?

Regards Bobcat. A4 Avant 3.0tdi Quattro