PartEditor  Constraints Menu and Toolbar
In the PartEditor, use the commands in the:
•  to add sketchelements. The toolbar is to the left of the graphicarea. 
•  : to add Constraints to, or between Geometry. The toolbar is to the right of the graphicarea. 
Note: Geometry includes the sketchelement, and its startPoint, endPoint, and centrePoint.
IMPORTANT: MD14.2.120+
To delete a Constraint: To delete a Constraint you must show the Constraint in the SelectionWindow.
1.  SHIFT+CLICK a sketchelement  or  its startPoint, endPoint or centrePoint, if the Constraint is between any of those Points. 
The sketchelement and its Constraints show in the SelectionWindow.
2.  Rightclick the Constraint 
In the contextualmenu:
To see ONLY Geometry in the SelectionWindow:
•  Click a sketchelement, or its startPoint, endPoint, or centrePoint 
PartEditor: Constraints menu
PartEditor: Constraints Toolbar
In the PartEditor, the is to the RIGHT of the graphicarea.
MERGEPOINTS : Deletes a Point. You cannot remove a 'Merged Point'.
•  Use MergePoints to join sketchelements endtoend, and remove one of the Points. 
•  Use MergePoints to make a . 
COINCIDENT CONSTRAINT : Does not delete a Point. You can delete a CoincidentConstraint later and move the Points apart again.
•  Use a CoincidentConstraint to move together two Points, or a Point to a Line, or a Point to an Arc or Circle. 
•  Use CoincidentConstraints for 'construction' geometry. 

You cannot overconstrain a sketchelement in the PartEditor (SolidWorks allows you to overconstrain, but you are given a warning).
For example:
A Point has 2 degreesoffreedom (DOF). It you add a 'coincident constraint' between a Point and a Line, you remove 1 DOF, and 1 DOF remains. The Point can slide along the Line.
You cannot then add a new constraint between the same Point and a Point at one end of the Line. A constraint between a Point and a Point would remove 2 DOF, but only 1 DOF that remains.

1.  SHIFT+CLICK a sketchelement in the graphicarea 
The sketchelement and constraints added to it, show in the SelectionWindow.
2.  Rightclick the constraint in the SelectionWindow 
3.  Click Delete in the contextualmenu 
