The Window Expander for YouTube maximizes YouTube videos in the web browser eliminating all white space and other texts. This is different then the fullscreen button in that it does not change the size of the actual browser window, it just fills the window with video. This is particularly useful for multiple monitor setups.
Version 2.3 adds support for HTML5. Note, the features such as setting resolution currently do not work with HTML5 videos; however, expanding and minimizing does work.
Version 2.2 removes a popup when the resolution of the video could not be found. Its a result of my debugging a previous problem.
Version 2.1 added support for https.
Version 2.0 fixed the quality not being set properly on expanded windows bug.
Version 1.7 new features: you can now set a preferred quality level for YouTube Videos. The options include small, medium, large, 720p, and 1080p.