UI Color plugin works very slowly in Firefox - It can freeze the browser.

[Jakub Ś]

To reproduce:

1. Open UI color sample and open UI color dialog
2. Grab the circle and move it a little bit.

Results:

1. Firefox 3.6 - works rather smoothly but IMO after closing dialog it was hard to get any response from page for few seconds
2. In FF16 - Colors don't change at once and you have to wait sometime after closing dialog to get browser response.

Please note that problem can be reproduced from CKEditor 3.0.2 but in CKE 4.x the performance is much worse than in CKE 3.x