It seems that the extension panel in photoshop (currently using 2015.5 on mac) is not color-managed. Plugins like Adobe Color Themes (formerly Kuler) or Coolorus don't seem to be usable with an AdobeRGB or a prophotoRGB profiled image because the hex values given by these plugins obviously don't match the values in a different color space.
Soft proofing my image with a different profile shows that the extension panel seems to work in a standard sRGB space, like web browsers. Which makes sense given the architecture of those panels.
Is there a way to have the plugin panels work in a color managed environment as well or are we condemned to use them solely on sRGB/SWOP pictures?