The recommended video sidebar fix breaks the sidebar when using Youtube Bigscreen with Firefox (ver. 21 and 22). Youtube Bigscreen (for Firefox) removes the sidebar tweak so you can still use Youtube Bigscreen until there is a solution found for the sidebar.

Release notes:

4.0 - Fixed sidebar background after YouTube update.

3.0 - Fixed player position and finally fixed sidebar position fixed. Tested in Firefox 23.

2.0 - User channel page images and space between the video and comment section have been removed on user channel pages. Large HD video resizing has been fixed to match YouTube's current code so that videos will resize properly.

1.0 - initial release