I frequently forget to first check what channel I have selected in the drop-down menu before changing the blending mode/opacity on a layer, and I think it'd be nice to have the option to switch between a drop-down menu and buttons, like the channel buttons in the Properties tab. It's just a little visual cue to make it more obvious, so it doesn't take 5 seconds wondering why messing with the blend mode/opacity isn't doing anything, just to realize you were working in the wrong channel.