I have been fooling around a little bit with color-themes and also the new
emacs 24+ custom themes, and find that (perhaps because of using
desktop-mode) there are certain traces of the theming that get left behind
in the display even when I've restarted Emacs after trying hard to erase
them.

One of these is the frequent appearance of pale stars even when
org-indent-mode is turned on.  See the attached screenshot for details.
The initial stars in a lower-level headline are visible, as are leading
stars in front of the indented text.  I find this quite distracting! Does
anyone know what might be causing this, how I can get rid of them, and also
how I would in general go about figuring out how to identify the cause of
similar appearance-related issues in Emacs?

Thank you!

Matt