Follow up from #1340, for the appstore packaging only.
We should probably deal with #1253 first. Then hope they understand what xpra does so they can drop some of the silly checklist items (ie: "Quit" should really be "Disconnect" to prevent confusion)
The appstore version (or maybe both) should use the native file dialog, see Notes on native OS X save/open dialogs in PyGTK using PyObjC
Another developer gives up the appstore: Goodbye Mac App Store: complying with Apple’s sandboxing and feature constraints to get them approved for sale would have required significant rewrites... (worth reading in full, has more links)
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1366