Version 1.2 (first release)
Features (in order of the css code):
- Minimum size: You can resize the window to be even smaller
- Changing background: New background for every chat. You can replace the url with something you like
- Introduction: Minor changes on start screen (info about this userstyle)
- Search bar on top: When scrolling through the chat list, they will appear behind the search bar
- New features in 1.1: little animations in profile pictures when selecting / hovering over a chat in the chat list; animations with emojis in the emoji list
- New features in 1.2: warning-popup redesign (see screenshots), nicer color for your chat messages and the image on the start screen

To disable any feature, just go to the feature headline and replace the "===*/" with a "===*" in the code.

If you want to give me feedback, you can post on the https://www.reddit.com/r/userstyles/comments/4uooy7/userstyle_whatsapp_web_improvements/.