Hopefully I'm not repeating other peoples posts, but I've been looking all morning for a solution to this problem.
Every modal popup in my site can be moved to the top, bottom and left without issue, but as soon as the popup touches the right edge of the browser window it jumps back to the middle. Also if you keep dragging the mouse after the popup has jumped back, the semi-transparent "lock out" looses it's transparency and you can no longer see the page behind the popup.
After playing around I found that removing the style="height:100%;" from the html element or removing the doctype declaration, I can now drag the popup to the right without issue. However, applying either of these changes messes up the rest of the sites layout.
I noticed that if the modal popup contains a textbox with an auto AutoCompleteExtender attached to it the issue was more pronounced. When dragging the popup to the right it jumps back before it gets to the right edge.
Example page (without AutoCompleteExtender):
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs"
<%@ Register Assembly="AjaxControlToolkit" Namespace
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