The Marks Bar can be enabled per Mark Collection in the Mark Collections docker. All marks have a duration, but it may not be relevant for all usages of marks. The Marks Bar provides additional functionality in the form being able to visualize that duration of the Mark. The primary use for this is for Lip Syncing faces. These marks can have text and that can be used to mark the locations of phrases, words, and phonemes.
Marks are still added via the right click functionality in the ruler. Right click on the spot in the ruler you want the mark to start. A default mark will be added to the active collection. The active collection can be set in the Mark Collections docker by checking the box in the Pencil column next to the collection that should be active. Holding the Control Key while right clicking to add a mark will have it fill the time between the two marks you add it between. You can add text at the same time the mark is added by holding the Shift key while right click to add. Adding the Control Key to that additionally will have it fill the gap between two marks.
The Mark bar itself allows for editing the marks. You can drag their start and end times or the entire mark in the same way you manage effects in the timeline. Dragging in the middle area of the mark will move the entire mark left or right along the timeline. Dragging the beginning or end of the mark will allow you to move those respective times. You can select multiple marks and then drag them right or left along the timeline as a group by dragging in the middle of one of the marks. Similarly, you can drag the start or end times of all selected ones uniformly by dragging the start or end of one of the marks left or right. Marks can also be moved by dragging the Mark indicator in the time ruler. While editing marks alignment marks will be projected up through the audio waveform to assist in alignment.
Holding the Alt key and double clicking on a mark will cause it to expand and fill the time between the mark prior to and after it. Right clicking on the mark will invoke a context menu that allows various functions such as Cut/Copy/Paste, Delete, and Edit of the text. Marks can be Cut / Copied along the timeline and can be pasted across collections.
An additional feature allows the the user to play a section of the sequence by double clicking on a Mark. When double clicking a mark, the editor will play the sequence over the range of the mark duration in a single pass and stop at the end. If the Loop function of the sequence is enabled, then that duration will loop until the stop button is clicked. This can be very useful in aligning marks to audio especially when doing lip sync. The marks can be moved while it is looping, but the section of the sequence that is playing will not reset until the loop is restarted.