Highlight color palette only shows colors from the last source

[oandregal]

Related #16014 #36841

Description

The color palette component used to highlight RichText content only shows colors from a single palette (default, theme, or custom). This has some weird side-effects such as when the user has added a custom color only that one will be shown.

Step-by-step reproduction instructions

• Use TwentyTwentyTwo theme.
• Go to the post editor and add a paragraph.
• Select some text.
• Open the "more block tools" in the block toolbar and select the "Highlight" option.

The color component only shows colors from the theme, when it should show defaults, theme, and user colors.

If the user adds a single color to the custom palette (via the global styles sidebar in edit site), only that single color will be shown here.

[Mamaduka]

I'm removing this issue from WP 5.9 board since we're already in the RC phase.

Let's try and land a fix for this in a minor or major release.

[roborourke]

I ran into this recently too, so still a problem. I'll see if I can work out how to support it.

[webmandesign]

I can confirm this is still an issue.

[webmandesign]

However, the issue with Highlight colors seems quite complex: #47439, #40279, #59649

[DamChtlv]

As of WP 6.5.3, i can confirm it's still an issue

[zoharma]

Still happening on 6.6.2 and Twenty Twenty Four. Does not makes sense that I cannot select from theme colours if I have set up custom colours. Please show all available theme and custom colours even if they are not grouped