because the tigra is a tiny car with a massive rear door, when you close the rear door loads of air is forced into the car. the window opening simply lets the air out. sorry should have explained it better in the first place.
hi
i have a Tigra as well and it puzzled me for ages. But my hubby explained that it was to let the pressure out - your windows probably explode otherwise!!
With my car, the last door I close always needs a harder push to close than the others, as TOMTECH says it is probably because of the air pessure in the car, never thought of that!
its because the first batch of tigras manufactured were being took back to vauxhall because ppl were closing the boot and the force on the roof was smashing the 2 side windows.so vauxhall rectified the problem with the above solution.