VBD2 is closed. Please go to https://vbd3.co.uk instead.

I have the impression that there is some kind of link between leaving feedback and starting a dispute. I think it is that if you leave positive feedback, you cannot start a dispute, but if you leave negative feedback you can. (I'm not sure about neutral feedback.)
Is that correct, or does leaving any kind of feedback close the door on starting a dispute?

I'm not 100% sure, but I don't think there is any relationship between leaving feedback and opening a case in the resolution centre. It has to be opened in the timeframe (was 45 days but paypal terms are changing to 180 days). I presume most cases would be for items not as described where problems occur or issues transpire after initially receiving the item, checking it and leaving feedback.