Collapsable sidebars in backend layout / column visualization

As a content editor, I would like to have a more compact layout to work within the content editor especially in long content models.

The black menu panel on the left could be collapsed, same with the white one as well.

If both panels are minimised then the form could split into two columns.

We have launched a revised interface for the CMS allowing what you were asking.

We have decided against the two columns form, but the rest of the interface is much smaller now!