"Use for Write windows" always enabled, cannot turn off.

[RainbowMagicMarker]

I'm experiencing an issue where, regardless of my settings, when I open the "Write" function or attempt to reply to a message, I get two Thunderbird icons in my system tray. One is my main Thunderbird window and one for the "Write" menu, which does not go away when the message is closed or sent.

Running Thunderbird 45.3.0, MinimizeToTray revived 1.3.2

[NouGithub]

I can confirm the same problem. It's rather annoying.