Typically, constraints are inferred between the view geometry and the section line. In most cases this is sufficient. However, under exceptional circumstances you may need to add additional constraints.
- Click Layout tab
Modify View panel
Symbol Sketch. 
- Click the section line to constrain.
The symbol sketch mode starts. With the exception of the view geometry, all geometry (including the section line) is dimmed. A polyline that coincides with the section line indicates the cutting plane.
- Add the required constraints to constrain the cutting plane.
- On the ribbon, click Finish Symbol Sketch.
The cutting plane converts to the section line. The construction geometry becomes invisible.