i must say it again … a selection (block) should take effect on single columns - not the whole track …
in general Renoise column feature is great but with not enough column-subfeatures it’s hard to work with more than 2 columns … no mute, no single selection …
please please … developers … improve the columns
cheers, Alex
Indeed, I experiences somes slowdowns when working because of lack of editing commodities for the columns. Especially with the “Insert” command, for delaying the track 1 line further, that should also be applicable for the current column only 
Looking’ forward to that ! 
If I’ve understood what are you talking about, you haven’t looked forward for it properly 
try CTRL+SHIFT+INS with cursor over the desired column.
It also works for command columns, as any other similar command…