Binary Space Partitioning broken on macOS Catalina, through various issues with window/event detection

[MutatingFunc]

System

• Amethyst version: 0.14.2 or 0.14.3b (Latest release & dev, older versions untested)
• macOS version: 10.15.1 (Catalina)

What's the problem?

When in Binary Space Partitioning:

• Windows are laid out as if no windows have been closed.
  (Renders the layout unusable)
• Existing windows when Amethyst is launched are not detected.
  (Renders the layout inconvenient unless used continuously from user login)
• New windows do not respect the setting to automatically make them the main window.
  (Minor annoyance)

How can it be reproduced?

Appears to happen every time.

What applications are involved?

Appears to include all applications.

Has anything fixed it, even temporarily?

Relaunching Amethyst clears the set of ‘ghost’ windows, but the issue returns when a window is closed.
No Amethyst settings tested resolve the problem.

dotfile (if you have one)

Just using the Amethyst app & menu bar UI.

Screenshots

Problems are as described, would rather not provide screenshots unless necessary.

[ianyh]

Opened #923 to track the main pane setting.