Create Hatch by Spline option is added to the Local Section View automenu.
Upon selecting this option, click on a drawing sheet.
If cursor is inside boundaries of any existing projection (the projection gets highlighted in this case) at the moment of clicking, then the spline command will be launched:
Upon finishing spline creation, the system returns to local section view command and selects this spline as a section boundary.
If cursor is outside boundaries of any existing projections at the moment of clicking, then the projection selection dialog appears. Upon selecting a projection, the system launches the same spline command as described above.