What problem does this address?

Currently the columns block will always go to a 50/50 layout at browser widths between 600px and 781px, and 100% at widths below 600px. This is regardless of the number of columns or customized column widths.

There will be instances where it is preferable to keep columns at their above 781px layout, even when viewed on narrower screens, so it would be great if the columns block could have an option to "turn off" the responsive layout.

What is your proposed solution?

Give the columns block something like a "not responsive" or "do not stack on mobile" toggle.