The Barebones Player would be JWplayer it is a default Flash Player it will show up as a Red play button on the IQS player. It plays .mp4 files if you have the older divx 1.x player plug-in. As the older Divx player didn't support .mp4. The newer Divx web player 2.x will play .mp4 so if you have the newer divx player 2.x then the play button will show up Blue.
And if you have the VLC player plug-in then the player will show as Orange. VLC will play .mp4.
The only way to get back to the way it was is to Disable the VLC plug-in and prolly the divx web player you have (if it is the newer version 2.x), and then Re-install the older Divx Player 1.x
Here is the older version 1.xWindows (DivX Web Player 1.5)Mac OS (DivX Web Player 1.4)
Now you should only have the 1.x version Divx web player in your browser extensions/plug-in's , and now when you load a host it will show 1 play button depending on what file format your watching it will be Blue for .avi and Red for .mp4 The only problem with this setup is that you will not have any player to support .mkv
It could be possible to have more than one plug-in and then just disable/enable depending on what you need at the time per file format.
I hope this makes sense and helps you understand what and why you have different player buttons.
I don't stream anything as I download and watch after with VLC stand alone player and then delete the file.