Comment 17 for bug 171579

> not registered as open: minimized docked dialogs

Confirmed. Hidden dialogs are considered closed in the patch. Maybe a third visibility value (or a specific parameter) should be added to handle the hidden status.

> I haven't yet fully figured out what happens when working with multiple document windows opened from within the same Inkscape instance.

The status is updated when the dialog is opened or closed, and doesn't necessarily reflects the status of the last closed Inkscape window. Thus with the following sequence:
1. Open a dialog in a first Inkscape window.
2. Open a second Inkscape window.
3. Open the same dialog as in the first window and close it.
4. Close the second window.
5. Quit Inkscape.
the next Inkscape instance will have the dialog closed.

I'm not sure it's very often used, but when you group dialogs in the same floating dialog window (to create a floating group of dialogs), the grouped status is not saved, and the dialogs are restored as independent floating dialogs. But this one is probably a bit harder to implement...