It never occured to me that we could use the tagging system to group palettes and be able to display the groups we choose, neatly separated from one another. Great idea, I like the mockup a lot!
I am not sure if it is the right place to discuss this, but one thing I am missing is some arrangement options for the colors in a group: Arrange the selection by Value, Saturation or hue for example.

@dkazakov That is a good point. There is a big amount of blending modes and it can be overwhelming at times.

@woltherav
At the moment you cannot see what you do beyond the canvas boundaries, so it wouldn't really serve that purpose. It would make sense if we had a bleed area like layout software (coreldraw,illustrator, etc), where you can actually see the whole image. But perhaps this goes a bit too far..

These options could help, although in practice it is almost the same effort as trimming the layer to image size or manually cropping the image. You require the user to take an extra action to trim the layers to image size.
I personally do not have any use for the strokes beyond image boundaries, and would like to have a default setting that prevents it from happening.
I understand that others might have use for it though, so this is where the bleeding space idea came from.

Another idea would be to define something like a "bleed" area in pixels, in the document settings.
For example:
We make a 1000 x 1000 px document.
We define a bleeding space of 200px. That would create something like a "buffer" zone around the canvas, so that the strokes are not cut at the image size but they can be extended by 100px more in each direction.
This will give us more control over the whole thing. The strokes won't be able to extend to infinity, but we also maintain the "stroke beyond boundaries" feature. If we want the strokes to end at the image size, we simply do not add any bleeding space (0 pixels)

You cannot draw outside the canvas in PS. But if you move/resize the layer, so that part of it is out of the canvas borders, the information is preserved. The same is true if you paste an image that extends beyond the canvas boundaries. You can trim these pixels by cropping the image.

We could have a palette generated from the color image's history.
We could have palette files embedded into the *.kra file. Which would then be autoloaded somehow?