Maybe it would be a help for user to support the following part of the text with a screen shot, so user knows exactly how to change between One and Two Column layout. The text part that could be improved by a screen shot says:

Shortcuts
The following keyboard shortcuts are available when the browser view has focus. Note that some of them only work when the view is using the two-column layout (you can switch between the one- and two-column layouts using the panel menu in the very top right corner).

Relevant documentation link:
file://localhost/Applications/Unity 5.0.0b20/Unity 5.0.0b20.app/Contents/Documentation/en/Manual/ProjectView.html