One feature that may have gone a bit unnoticed in recent versions is the ability to change the application layout. It is mainly aimed at plugins, so that they can create a panel anywhere, and you can then move it wherever you want, but it can also be used to re-arranged existing application components.
For example, you can put the note list below the sidebar, to have more space for the text editor, move the sidebar to the right of the application, etc.
To begin changing the application layout, click on "Change application layout" from the View menu:
This will put the app into a special mode, from which you can move the side bar, note list and text editor around. You do so by pressing on the arrow keys:
For example, pressing the left arrow on the note list would move it to the left, just below the sidebar:
Once you're done modifying the layout, press the "Escape" key to exit.