collapsible column flyout

[ashifolfi]

This could be very useful for things like messages/certain DMs you want easily accessible or for a certain column you want to keep an eye on without having to move it around or constantly scroll back.

The idea is for it to by sort of styled like the messages flyout/popup on standard twitter/tweetdeck when collapsed and have the standard column appearance when expanded.

I looked into doing something like this with CSS but couldn't figure out how.