Simple Trick To Pick The Blended Colors

Pls, check the attached video!!!...

I have a gray bg, a yellow dot, and a transparent pink circle
if I wanted to pick a color between these 3 colors, I can easily pick gray and yellow because these are in full transparency
but if I pick the pink color, ill get a color which is a blend of yellow- pink or gray-pink
but if I want to pick the pink color in its original nuance, that is not possible because the colors with transparency will always blend with the background color,

to solve this, there is a simple trick,

turn off all the background layers to make it transparent,

now pick the pink color it will be in its original nuance.

That's all, Thanks