"Stylesheet could not be loaded"

[MiguelDebruyne]

Firefox gives an error "Styleheet could not be loaded." because of this extension when going to the Style editor tab in the Developer Tools. It's a little nuisance when developing websites with this extension on. Had to manually deactive extension per extension to see which one gave the error. I've had times when I had a stylesheet that could not be loaded but because of the error this extension gave I could not see which one.