CATIA newbie constaints question 1

[analogsoul]

Hello there. I have a question about constraints in CATIA v5. I have the two parts shown in the picture in the assembler. I want so to constrain them that the flat part moves only on the plane and line such that it slots into the ring. I have added coincidence constraints to the planes and lines, but I can still move the parts out of position with the compass. When I click 'refresh' however, they snap into position. What am I doing wrong? Any help greatly appreciated.

 

[KevinDeSmet]

You need to hold SHIFT in order for the Compass to move respecting the constraints.