Create an image, go to "image > convert image type" then undo, the convertion of the color space of layers isn't undone.
same problem with just converting a single layer.
That problem is fixed... But there are two other problems: * if there is just one layer, the optimization kicks in and on undo, painting on that layer is broken until another layer is added * the canvas isn't always updated
These two issues seem fixed, however, painting on a converted layer is broken. Something with the composite op. I'll add a different bug for that.