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 show or hide constraints for selected geometry, click
Sketch tab
Constrain panel
Show Constraints
then select geometry.
To delete a constraint, click to select the constraint glyph, then press the Delete key (or right-click and select Delete).
Note:
- To hide or show all glyphs of a certain type, use the Constraint Visibility dialog box.
- 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. Conversely, point to a constrained geometry 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.