Review for MinimizeToTray by factor
Rated 5 out of 5 stars
This extension is a must if you keep checking emails all day long. Though it will keep Tbird's memory allocation at full, unless you add a New Boolean value in the Config Editor (config.trim_on_minimize) and set to "true". If you have Lightning installed, the calendar won't keep the correct day, unless you exit and restart.
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