The display automatically updates every 30 seconds or so and moves to keep track of the current time, so events will slowly move across the screen as time goes by. A red line which does not move shows where the current time is.
The timeline can be toggled on and off from the Timeline option in the View menu in the same way as the status bar can be. There is also a right click menu which toggles Events, All Day Events and Tasks on and off, available from the timeline. Unfortunately, it does not yet show the status of whether these options are on or off.
The timeline can be zoomed in and out, either by using the scroll wheel of the mouse, or from the timeline's right click pop-up menu. Degrees of zoom go from an hour taking up 256 pixels to 28 days being displayed on the timeline. extensions.timeline.log can be set to true in the advanced configuration editor to see a list of events and tasks fetched as messages in the error console.
Version 0.4.2 is compatible with Thunderbird 17 and up. Version 0.4.1 is compatible with Thunderbird 5 to 16. If you are using a version of Thunderbird below version 5, please use version 0.3.3 of the add-on instead.