DHTML Window Widget - for IE window after moved top side and when move down cant rel

[aswinreve]

http://www.dynamicdrive.com/dynamicindex8/dhtmlwindow/dhtmlmodal.htm

for IE Browsers when i drag to top side of browser and when i move down the same the cursor cant release it it drag automatically with cursor, but left side and right i can move and release the cursor and drag it anywhere

Please help me how to solve this


regards
aswin