Hi Matt,
Yes, the bug has been fixed in VFP Advanced.
Please refer to the file history.txt:
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2016/9/5
1, VFP 9.0 Fix19 - SYS(9000) Automatic Dock The Dockable Windows ok.
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2016/7/15
1, VFP 9.0 Fix18 - Moving The Dockable Windows ok.
Best regards.
Chen
2017.3.30