Tracks in the timeline can be grouped in a variety of ways, as well as hidden, deactivated, etc. The options are as follows:
Group tracks can be used to group any types of tracks. These groups of tracks can jointly enabled/disabled and displayed/hidden. See Adding group tracks.
Similar to objects, you can also create track groups. Clicking one track in a group causes all tracks in this group to be marked, allowing you, for example, to adjust the track height for all tracks or muting all tracks in one go. See Grouping via track groups.
Right-click a track head and select Insert track 
Group.
Grab the group track head at the point structure 
between the buttons and move the group track until it is located above the tracks to be grouped.
If necessary you can add further group tracks likewise. One group is made up of all the tracks located below the group track down to the next group track.
All tracks of a group can be displayed or hidden. Click on 
to hide or on 
to display the tracks. If you press the Shift key additionally, all tracks can be displayed or hidden in one go.
Use button 
to deactivate or activate all tracks in a group. This works even when the tracks in a group are hidden.
The area with the point structure can be used to grab and shift group tracks. The tracks in a group are also shifted when they are hidden.
Hidden tracks cannot be marked or selected.
The contents of hidden tracks are also played back.
Similar to objects, you can also create track groups. Clicking one track in a group causes all tracks in this group to be highlighted, allowing you, for example, to adjust the track height for all tracks or mute all tracks in one go.
Mark or select the required tracks ... See Marking tracks.
Right-click the track head of one of these tracks and select Grouping 
Create new group. In the track head, the group index is displayed to the right of the track number, e.g. 3|1.
Mark or select the tracks to be added to a group.
Right-click the track head of a marked track and select Grouping Assign group.
Under New enter the index of the group the selected tracks should be added to, followed by clicking OK.
Mark the tracks of the group to be added to another group.
Right-click the selected track and choose Grouping Change group.
Under New enter the index of the group the selected group should be added to, followed by clicking OK.
Click the track head of one of the tracks in the group
Right-click one of these objects and select Grouping Remove grouping
Right-click the track head of a track which is not part of the group in question. This deselects all tracks of this group.
Right-click the track head of the track to be removed from the group and select Grouping Remove grouping.
See also: