The Grips (or "dots" at the ends of respective corners) at ProSteel objects are a helpful tool in order to adjust the parts: lengthen/shorten of shapes, stretching of plates. Sometimes you may happen to find they are not working properly like the stretching doesn't work precisely any more. So, this wiki will guide you to avoid this issue.
1. Open the Global Settings or Options by holding the right mouse button in the View window and then click on the Options.
2. Under the Grips page, set the Increment value to zero for Shapes and Plates as shown in the below image. When you have entered a value > 0 in the Increment input field, the length of the shape or plate can only be changed via handles in preset modular steps. When you have entered 0, any kind of change can be performed.