Merge pull request #2133 from zonkmachine/knob-update

Update knob after changing response 'lin/log'

src/gui/widgets/Knob.cpp

@@ -497,6 +497,7 @@ void Knob::contextMenuEvent( QContextMenuEvent * )
 void Knob::toggleScale()
 {
 	model()->setScaleLogarithmic( ! model()->isScaleLogarithmic() );
+	update();
 }