Inference lock does not work

Layout

Using the Shift key to lock an inference won't work with the Rectangle tool because the Shift key has a different function there: it forces your rectangle to become a square.

However, with the Move tool and the Line tool, you can use the Shift key to lock an inference. Additionally, you can also use the arrow keys to lock inference directions:

Use the left/right arrow keys for horizontal directions. Use the up arrow key for the vertical direction.

Use the down arrow key to switch between perpendicular and parallel to an existing line.