You can use a marquee selection to select multiple notes and notations at the same time within a specific area. You can do this in Write mode and Engrave mode.
Procedure
Result
When you release the mouse, all notes and notations in the area within the gray rectangle are selected.
Note
Only items completely within the area are selected. However, if any part of a note/tie chain is within the area, the whole note/tie chain is selected.