Aha! That is not what I thought of, but that is very useful too, indeed! Thank you.
What I meant; most often I need to adjust highlights and shadows in all channels equally, which to me means adjust all RGB sliders to the same value, like this example:
Gentle adjustments that are the same in all three so color balance is kept: Lift is 0.4 for all channels, gamma is 0.21 for all and Gain is 0.29 for all. It is more rare that I need to adjust each channel separately, but it does happen too.
That is not only for this effect, it is valid for all effects with RGBA controls. The need to adjust all three simultaneously happens way more often than need for individual channel adjustments. I was hoping for a trick (modifier key, option etc) so I could adjust one and the others would follow simultanteously.
(This is actually artistically more important than time-saving, because the way it works now, with adjusting R and then G and then B to the same value, this shifts the hues of the image during this process and then I loose my aesthetic “sense” and goal when colors are whacked out of balance, hard to explain, but its like tuning a violin when somebody else tunes another violin next to you, its hard to focus exactly right, but doable, but needs double-extra focus and double-checking, maybe it makes sense…?)