How to stop backgrounds from changing every time an external monitor is plugged in?

[SolarCanoe]

I use a macbook running Yosemite and half the time I have an external monitor plugged in so I can have 2 desktops. Every time I plug it in though, it either creates a 3rd desktop, or it changes my background image. Does anyone know how to fix this? Does it drive anyone else crazy?

Thanks

 

[spektrality]

This is been driving me crazy for the past few months, it happened in Mavericks too. I honestly want to stop OS X form creating more desktops, I don't use the feature.