I will describe you a problem that I have experienced with jQuery dialog in IE8 (but I guess that it can be reproduced on other versions of IE too).
The problem appears when you create a draggable dialog and you want to set a height to it, and the problem is that when you drag and drop the dialog multiple times then the dialog height will get smaller.
If you notice such a strange behavior then you need to know that this is because of the height that you have set for the dialog.
When you set the height of the dialog something wrong is happening inside the jQuery library.
How to fix this?
Try to avoid setting the height of the dialog where possible.