make selected area more visible

[MCLV-pandorabox]

It would be so handy if you could actually see the area like the way worldEdit or postool work, and not just position 1 and 2

[SmallJoker]

Yes. That would be nice. Feel free to propose a PR if you'd like to work on this feature.

[fluxionary]

this is something i'd love myself, but have never gotten around to doing. i'm not sure when i'll get around to it though.

[tigercoding56]

worldedit does this.
in the worldedit.mark_region function of https://github.com/Uberi/Minetest-WorldEdit/blob/master/worldedit_commands/marker.lua
you could just make a optional depends