Script Summary: Disables the reddit sidebar by default and re-enables if tab-menu option is clicked.
You can also add this as a bookmark and run it manually.
Then create a new bookmark and paste the code as the URL.
Save the bookmark.
Navigate to a reddit page like http://www.reddit.com
Once the reddit page has loaded, click the bookmark.
You should now see the sidebar disappear automatically.
A new tab appears on your top-menu called "Toggle Sidebar".