That's a good question. You didn't show a class, though, you showed a sub. If that sub was part of a class, that would likely be the reason, but if you actually meant sub or method rather than class, and you wrote it exactly as you showed (just plain label11.Backcolor, not Form1.Label11.Backcolor, or any other variation), then the problem has to do with where the method was found or how it was called, or something like that, because the method itself isn't a problem.