Dialog positioning bug when viewport is scrolled (IE and FF)
When a jQuery UI dialog is opened (centered in viewport as per the default settings) in a viewport that is scrolled down, trying to move the dialog by dragging causes the dialog to jump down quite a bit and it might even disappear off screen. The "jump" seems to be proportional to the amount the viewport is scrolled.
I've encountered this bug (?) in Firefox and Internet Explorer, but not in Chrome or Safari (tested with current versions on Windows 7). I have not performed extensive testing or debugging, as I'm not qualified to do so. I'd appreciate any input on this before I file a bug report.
Minimal demo here:
http://jsfiddle.net/tomas_eklund/EygDN/