Use nvgGlobalTint() instead of nvgGlobalAlpha() for un-tinting lights.

src/Scope.cpp

@@ -302,7 +302,7 @@ struct ScopeDisplay : TransparentWidget {
 			return;
 
 		// Disable tinting when rack brightness is decreased
-		nvgGlobalAlpha(args.vg, 1.0);
+		nvgGlobalTint(args.vg, color::WHITE);
 
 		float gainX = std::pow(2.f, std::round(module->params[Scope::X_SCALE_PARAM].getValue())) / 10.f;
 		float gainY = std::pow(2.f, std::round(module->params[Scope::Y_SCALE_PARAM].getValue())) / 10.f;