Help-DistanceJoint2D doesn't keep distance fixed when it's added as a component to an object on runtime

I intend to create a rigid rope, between the ball and a certain point. I add the component to the ball at runtime (in the Start Routine, just to test), and I can see it created in the inspector, but the object keeps falling anyway. If I update any value of the DistanceJoint2D in the inspector during runtime, it starts to behave normaly. This video summarizes my problem:

Can you guys explain this or point me in the right direction to solve this problem?

There is!
Insert the following lines after adding the component and it should work:

joint.enabled=false;
joint.enabled=true;

Good luck