Columns are a natural part of any outliner
I'd love an implementation like moo do does it!!! (https://www.moo.do/). You can add as many columns as you like (panes) and shift items easily from one pane to the other. It really adds another dimension to an outliner, as you can use it for a kanban board. (Thanks for the css hack that Kirill posted recently! But a full column implementation would be awesome and increase the possible use-cases (= potential users :) )
Adam Kagan commented
Please add columns!!!!! It would make this outliner unstoppable.
Even a simple column implementation would be much appreciated. Like 1 or 2 columns right-justified.
David Rees commented
Ecco's column is a folder was very cool way of doing things.
Column please! something like omnioutliner
Columns would be great. If columns were added, it would also bring a whole level of functionality as utilized by Ecco Pro (a 90's Window's outliner/PIM that still to this day has a strong following).
In Ecco, (which is in my opinion the right way to implement this), a "column" is a representation of a "folder". "Items" (e.g. a line in an outline) can be added to any number of folders, thus when the folder is shown items in the folder are shown. Columns can be added to any "view" (e.g. an outline view that Checkvist currently has), and columns can designate the "field" (e.g. a piece of data such as a date, a checkbox, a word, a selection from an enumerated list, etc.) which ties the item into the folder. It's a real powerful way of approaching an outline, having items be a part of folders, and folders being able to be viewed as columns in a standard outline view.
If you need to check it out in practice to understand how it could be structured/coded, try the newly written 64-bit installer for Ecco Pro: http://www.compusol.org/ecco/