Remove the arbitrary restriction on line widths

The line widths are currently restricted to whole-number steps. That is problematic for me because I personally find width 2 to be too thin and 3 to be too thick for some of the pens. Kindly add 0.25 or 0.5 increments to the slider, or perhaps a text box where we can enter a custom width, (e.g 2.4). Thank you.