When picking colours per-se, either under styles or materials, I’ve often found finding a previous used colours or just picking set colours time consuming. The choice seems to be, COLOUR WHEEL, HLS, HSB or RGB. I’m thinking a simple COLOUR PALETTE/PALETTES would be good to simply the process. See attachment eg.
The Mac version of Materials, named Colors once you’ve opened it, does have that feature. I can go to a different application (I just tried using Pages), find a color I like, drag that color into the swatch area of the palette, and the same color is available immediately in SketchUp.
Assuming that the material palette is not going to be redone to have the better options from Windows and Mac, an easy work around is to make your own component, that is a bunch of rectangles all colored differently, ready for you to Alt-click on while using the paint bucket. That would work cross platform, and wouldn’t be limited to just colors. Something like this:
On the Mac color pallet the eyedropper tool also works anywhere on the screen to import a color. Modifier key “Command” while in paint bucket tool invokes an eye dropper but this one does not sample outside of the sketch-up window. Instead, the eyedropper tool at the bottom of the pallet does work anywhere on the screen. It won’t import materials but works for solid colors, which can be stored in the temp pallet below. Does the windows pallet eyedropper behave the same way?
The eyedropper in Windows seems to only pick up existing materials. It won’t pick up a color from the screen, even if it’s inside the SketchUp window, unless it happens to be part of a material, and then it picks up the material, not the color. Using Command while on the paint bucket works the same way for Mac.
There are two eyedroppers, one will pick up anything while the other is pure SU.