Switching display modes resets configuration
When using multiple displays, switching from the Join Displays mode to the Mirror or Single Display mode and back to Join Displays, the previous configuration is forgotten. This is especially bad when using the display-switcher keyboard shortcut, since no one would expect the shell to forget the configuration after pressing a keyboard shortcut.
Instead of resetting the configuration to default when switching between modes, the configuration should be remembered for every mode. Resetting the configuration should instead be possible by clicking a button labeled "Reset to default" or "Use recommended values".