Version: unspecified (using KDE 4.5.1)
When Desktop Effects are enabled if you choose "configure window decoration", then the configuration window open with the "desktop effects" option selected as usual. But it shows the "window decorations" option instead. If you click "desktop effects" it does nothing. You have to select another option first and only then select "desktop effects".
Minor bug but still a but.
OS: Linux (i686) release 22.214.171.124-0.3-desktop
KDE 4.5 (upstream, NOT factory)
*** This bug has been marked as a duplicate of bug 249706 ***