--- Comment #6 from Mirek2 <[hidden email]> ---
This is one of the problems that the sidebar brings -- now there are two
Navigators, two Galleries, and two Style panels. The benefit of individual
panels is that two can be open at a time, while the Sidebar includes features
not found in individual panels.
Ideally, the panels unique to the sidebar would be turned into separate panels,
and panels in general would be allowed to be stacked into tabbed groups, much
like panels in GIMP (or Adobe's tools).