I use Drupal for most of my sites. I use it in many different ways and it has been working real good for me.

On one of the sites, I use the ThemeKey module to select a different theme once you are logged in. This means, when I want to switch themes, that one theme selected for logged in users sticks, whether you disable it or not, it remains selected by the system.

And?

Well... one thing sticks from themes, their .info file. You just cannot refresh the cache properly unless you disable the theme, then re-enable it. (By the way, when disabled, don't go to the Blocks administration screen since that will scramble your existing selection if the themes are not equivalent enough.)

So here the solution was to go the the ThemeKey module setup. Turn off the automatic theme selection for logged in users, disable the theme in the Theme setup screen, re-enable the theme, then put the ThemeKey back to normal.

It took me a little time to figure it out...