A Dual Slider widget node would be useful.

There is a Demo of such a slider here: https://refreshless.com/nouislider/
and a link to GitHub download.

(So this might be an easy project? Maybe not. There is a lot of code)
There are some install instructions here: https://stackoverflow.com/questions/4753946/html5-slider-with-two-inputs-possible

I have not had time to see if it would be compatible with nodeeditor and MoI.

There would be a min value, a max value, and "p_value" slider, "grip" and "q_value" slider "grip".
min <= p_value <= q_value <= max. (I would also like 2 < q_value.)
For my Doyle Spiral Node, if I ever finish it.

- Brian