Use the icon that thunderbird uses

[theultramage]

Thunderbird's executable contains an embedded icon, but it seems the one shown in the title bar and taskbar is loaded from chrome\icons\default\ (the main window in particular uses messengerWindow.ico). However, mintrayr seems to just use the embedded icon. This causes a visual mismatch if the icon on disk is customized.

I don't know if that's the cleanest way to do it. There are theming addons that supposedly allow customizing/rebranding the UI. Do you think there's an API to get the icon that's being used?