Message: Some of the selected named colors are in use in your document
Cause
You have attempted to delete named colors from the document which are being used.
What Can I Do?
Clicking
Delete Unused deletes all the
colors you have selected apart from those currently in use.
If you click Delete
All, all the colors you have selected will be deleted, including
the ones being used. The objects which are using these colors will have
local colors
applied to them. The appearance of the document does not change.