I cannot interact with lines length

I am working in a figure and since this weekend I have an issue, which unables changing the length oo shape of anything I have drawn.

Vertez points are fully black, and thus enables only moving.  I would like vertex to be with the square inside in white when using the direct selection (A) and the square to appear when I clikc in the selction botton (V).

Thank you very much for your help!