Score elements selected in Fragment selection mode form a fragment of specific type. You can make corresponding actions on it or change properties of its elements. Fragment types have self-explanatory names: Musical events fragment and Bars fragment.
The fragments of this type contain one or more musical events on a single track.
If you want to select all musical events in the current track with one or more musical events already selected tap Select Track.
The fragments of this type contain one or more composition bars.
You can quickly change the current fragment type from Musical events to Bars by tapping Select Bar. In that case the bars what include those musical events become selected.
If you want to select all bars in a composition with one or more bars already selected tap Select Track.