To show or hide constraints for all active sketch geometry, select either Show All Constraints 
or Hide All Constraints 
in the status bar. Alternatively, press F8 or F9.
To highlight constraints for selected geometry, click Sketch tab 
Constrain panel Constraint Settings General tab and select Show constraints for selected objects. When displayed, any constraint can be selected to be deleted.
To display constraints when creating geometry or constraints, click Sketch tab Constrain panel Constraint Settings General tab and select Display constraints on creation.
Note:
- To hide a specific constraint glyph, right-click the glyph, and select Hide.
- Point to a constraint glyph to highlight all associated geometries and constraint glyph partners.
- Click and drag a constraint glyph to move it. The new position, relative to the geometry, is maintained when the geometry is moved. However, if you turn constraint visibility off and on, the constraint glyph reverts to its default location relative to the geometry.
- Deleting the Reference constraint has the same effect as selecting Break Link from the context menu; the reference geometry is converted to normal geometry and the associative links to the parent geometry are removed.
- When geometry is selected, you can access Delete Constraints
from the context menu to remove all constraints. Coincident constraints will not be removed.