The dropper next to the fill color of vector objects (in the Tool options when the select tool is activated) is not clickable. I'm assuming this is to torture us for our sins but I'm wondering if we can somehow improve on that. Maybe some tooltip saying "Click again, I assure you it should work" so that we try harder.
Jokes aside, any chance we could have a real dropper for this color?

That dropper icon is greyed out which suggests that it was intended to have that functionality but it's not yet been fully implemented.
https://bugs.kde.org/show_bug.cgi?id=335207 was raised five years ago so progress seems to be slow on that one.

(There's some 'interesting' behaviour in that area because when a vector object is selected, you can change just the fill colour by using the Advanced Color Selector or the Specific Color Selector (possibly other colour selector dockers as well) no matter what you're doing in the Tool Options docker.)

All you can do at the moment is use the standard Color Selector Tool (P) to pick a colour (including the opacity) and add it to a palette and then select that palette from inside the fill/stroke tabs to get your picked colour/opacity from there. It's very awkward but it works.

Ha, that wish you refer to now _has_ been implemented, since what it was asking for is that you can set colors on shapes with the standard color pickers, and that works now .

The color picker button is strange, I will have to look into why that's there. It looks like it's just an image not even a button.

Okay, I've checked the code. It explicitly hides and disables the button with the comment:

// TODO: for now the color picking button is disabled!

But there was one place where the button was unhidden. I've changed that for now and added https://bugs.kde.org/408777