Finalized the Scale Gizmo. Now it works properly.
Started bug fixing editing handles.
At rectangle, after rotation transformations applied, the editing handles are not displayed correctly. The information we hold on rectangle Node (two points and a normal on the rectangle plane) seems not to be enough to calculate properly the editing handle rotation matrix. Also today remembered that our 2 point rectangle tool has a restriction: it is drawn only having edges parallel with XOY, XOZ, YOZ planes. A solution to solve all these would be to implement a more powerful 3 point rectangle tool or at least enhance the 2 point rectangle to hold more info internally.