sun.awt.windows.ThemeReader caches themes data which is flushed on
ThemeReader.flush() call. ThemeReader.flush() is invoked from
sun.awt.windows.WDesktopProperties on any desktop property change. For
some reason when JFileChooser is up WDesktopProperties is notified
about property change constantly.
It seems there are two problems there:
1. JFileChooser causes desktop property change notification
2. According to MSDN documentation theme data should be valid until window receives
WM_THEMECHANGED notification. Thus ThemeReader.flush() should not be
called more often that that.

How to reproduce:
1. Put debug output into sun.awt.windows.ThemeReader.flush
2. build java
3. run SwingSet2
4. change l&f to Windows l&f.
5. Run JFileChooserDemo