It seems like you can`t eyedrop colorpick a color through a hotkey while painting if the colorpicker menu isnt open.
This makes it very tedious while trying to do more painterly things inside of substance painter
Currently whenever i switch to an eraser or smudge the colorpicker menu will close because its not dockable this means that when i switch back to a brush i suddenly can`t colorpick anymore using my hotkey.
I think having both the ability to lock the colorpicker menu to stay visible and be able to colorpick outside of it being open would make life a whole lot easier painting inside the app.
If the issue is that you don`t know what channel the colorpicker menu would be for then you could implement a dropdown for the channel inside of the colorpicker itself and make it dockable. By default most painting outside of masks will be done on the Albedo/Diffuse in my experience so having that set as the default sounds like it could work just like the viewport dropdowns work