problem with cotation lines

I apologize, english is not my natural language.
In a drawing, I set cotations : it's ok.
I draw a rectangle with dotted lines. When I set a cotation inside the rectangle, the dotted lines are replaced by a 'full line' from the corners where I clicked to the cotation line. How can I prevent this behaviour ?

TIA
Jean

Could it be that the baseline of the dimensioning (cotation?) is just lying over the dotted rectangle line? Set it a bit away with the third mouse click, be sure to have 'free snap' activated, so that the position of the dimensioning line will not snap to a corner of the rectangle.

That's it ! Thanks.

I have plaid (play ?) with snap options and I found the best one for what I wanted to do.

Jean