Create a Marker Track (The default name is “Markers”)
Hover over the name and the message box displays… Markers - Track Name (Use double-click to edit)
So double click, enter new name, press enter key.
New text is not displayed. 
Hello,
Just out of curiosity, why do you need to change the Markers track name?
Specially when you only can have one markers track…
I have created a bug report, but I am guessing this is by design.
Best regards,
GN
Technically I can work with the current nameing convention. However, I am writing some music for a video. I place the Marker track under the Video Track and use it to mark the Scenes. It seemed more logical to the customer who talks in terms of Scenes rather than Markers. Its not a show stopper but does help from a customer perspective.
As a side note it would be great to have another marker track, but I am guessing this would be so far down on the development list it would not be worth putting in a feature request.