I have a problem with the sketch. 

When I select the sketch on the front plane, what appears is shown in the attachment. 

Instead of one line/rectangle to choose from, hundreds are drawn depending on the movement of the mouse, and everything is mixed up (see the attachment). 

When I select the top/right plane, everything is fine, and I can work normally. The problem affects both the first sketch and every one on the part. 

The front plane is always incorrect, while the top/right plane is all good.  It's unreal to work with this bug. Any ideas?