I use the Divide Track List to have my marker track stay at the top of the track list at all times. There is unfortunately a bug that is driving me nuts and keeps messing up my marker track unless I lock it.
If I select the marker track and then select another track by clicking in the track name area (track control area?) to the left - everything works as expected = the new track is selected and everything is fine.
However, if you have “Select Track On Background Click” or “Track Selection Follows Event Selection” activated and you click the background in the lower Track List or click on an event/region - the new track is selected BUT the track in the upper track list is ALSO still selected as well. If you previously selected a marker this will also stay selected. The result is that if you for instance delete the track you just selected in the lower Track List you will ALSO delete the Marker track. 
To recreate
- Create a new project.
- Activate “Select Track On Background Click” and/or “Track Selection Follows Event Selection” in the prefs.
- Activate Divide Track List.
- Create a marker track in the upper Track List.
- Create an audio or instrument track in the lower Track List.
- Select the Track in the upper Track List by clicking on it.
- Select the track in the lower Track List by clicking on an event or in the background.
- Project/Remove Selected Tracks.
= Both the track in the upper Track List and the lower Track List is deleted since the track in the upper Track List was never deselected when the track in the lower Track List was selected.
As an added double trouble bonus - if you have a cycle marker selected and then select a region to change color, the cycle marker is never deselected so BOTH the region and the cycle marker changes color. It took me a while to understand why my cycle markers kept changing color. 
Workaround for now:
After you have done any kind of editing of the tracks in the upper Track List - make sure that you ALWAYS Shift + click on the track and/or event that is selected in the upper Track List to deselect it before you continue working with the lower Track list.
