Dialog DROP animation breaks dialog in ALL versions of Internet Explorer

Using the jQueryUI dialog settings {hide: "drop"}.

In Internet Explorer, the dialog animation fires on close as expected, however when you recall the dialog using .dialog("open"), the modal overlay appears, but no dialog - at first I thought this isolated to IE6, but same fault occurs in IE8 hence priority is major.

Everything behaves fine in Firefox. I suspect that as the "drop" animation whizzes the dialog out to the left and alters its position, but the position is not being reset when "open" is called again.

Workaround for now - don't use DROP ("FOLD" works fine!).