That's strange, it should just be tied to the main color picker - does it update if you select a new secondary that way?
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hey! sorry for the slow reply, I just saw this. no, it doesn't. even when I click on the secondary colour slot, and then anything on the colour picker (or pick a colour from the palette), it just changes the primary colour slot. let me know if there's any way I can help send some footage to you? cheers!