I have had this issue ever since I went with a 24 in monitor as my main monitor and a 19 in as my 2nd. In 1 part of the screen the the mouse will have to be above the button or skill I am trying to click and when I am lower on the screen the difference is not as much. To give a better example, I am trying to click on a skill in toolbar 3 with the mouse but to do it I have to mave my mouse over toolbar 4 just above it before it shows highlighted. It makes for some very hard looting when I your trying to just take one item. Its got me in trouble in more then once, just due to the extra time I have to spend on looting.
Is there a setting I am missing? If it helps, the Main monitor is a 24 in Acer and the other 2nd monitor is a 19 Acer. Both are connected to 8800GTS cards. I know I was told to connect both to the first card as I run a SLI setup. However I started running into a ingame lighting issue where I was having trouble seeing on 1 screen or the other. Only thing that resolved that issue was to put each monitor on a seperate card. Performance is not bad at all in fact. Both run at about 27 FPS average with no problems. Its just that mouse problem I can't seem to resolve.