The picker for switching between Gradients and Solid Colors is located at the top of the Color Picker. Is there an option to switch to the gradient picker for you?
You can bring up the picker by simply drawing a shape (e.g. Rect) and clicking on the fill swatch. Note that we do not support gradient borders yet and text can not have gradients. Once you choose a gradient, you can use the on-canvas editor to modify the stops of the gradient in place.
Below is an image of the dropdown on OSX.
Hope this helps!
I was referring to the W10 release link because I'm on W10 and not Mac. No, I have nothing like that going on here. My color picker is for flat colors only and no gradient option. No available update for Xd. So I guess we can add this to the "yet another inconsistent Xd release for W10" account. Let's hope it appears on the next Xd update, whenever that is.
This feature is definitely available in the latest release of Adobe XD for Windows. Can you check the About box and confirm you are running version 0.6.32.12?
If you have that version, there will be a dropdown at the top of the color picker popup. This is what the dropdown looks like on Windows (when opened):
Also, please note that gradients are not yet available on text, or in the stroke (only the fill can be a gradient), so you won't see the dropdown in those cases -- that's true on both Mac and Windows. If those use cases are important to you, please click the links to upvote those items on our UserVoice site.
Sorry for the late response but I had to delete Xd and re-install it in order to receive this gradient update for W10. It's there now.