Comment 8 for bug 171589

That is a very nice idea, I've often thought of the need to
have such a tool while working on Adobe Illustrator files.
For example, I'd be creating a set of icons with a reddish
color palette, and then get a request to do a similar icon
set in green. Other than change every shade manually, the
only option I got was to export to photoshop and change the
colors on a raster output. Now, Illustrator does have
something similar but it doesn't work on gradients, for some
reason. Not on CS1 anyway.

One point worth mentioning is that some selected shapes may
be using gradients that are also shared by other objects
outside the selection. In this case, Inkscape should
duplicate said gradients before working on them, so that
objects outside the selection don't have their colors
changed as well.