Hi, I just committed a little bit of code that allows to quit column-view with C-c C-c with the cursor almost everywhere in an Org buffer. Until then there was no such key offered.
The behavior is very similar to C-c C-c removing the highlights created by a sparse tree action. In particular C-c C-c can not be used for setting the tags on a line in column view state any more. But there is still C-c C-q to do this. Another way is using C-c C-c C-c C-c and then switching back to column view. AFAICT this is a little step to more consistency and it makes quitting column view more convenient. Please let me know if there are any issues with that change. Thanks, Marco