Draggable Dialogs are not positioning accurately in scrollable content areas

In IE and Firefox, when a dialog widget has been opened and is set to be draggable, the dialog will drag accurately under the user's cursor when it is in a scrollable content area that has not been scrolled. When the content area has been scrolled, clicking to select and drag the dialog will immediately cause the dialog to jump out of position by an offset amount. For example, the dialog might jump 400 pixels away from the user's cursor and then drag from that new erroneous position. It appears that the dialog's position is not being accurately calculated through the entire chain of parent and child offset position values when the dialog element is dragged.