I said everything in the subject. Even the "use this area to test..." entry doesn't changes. (However, the "Show blinking" box works.)
Created attachment 2661 Fix a typo in the property name There was a trivial typo in the property name, so the value was never stored in xfconf. Patch attached.
Fixed in master. Thanks for the patch! commit 2f9e6f6547eb695c6e77225d8c84af9bcb90e775 Author: Jannis Pohlmann <jannis@xfce.org> Date: Mon Nov 9 00:20:08 2009 +0100 Fix /Net/CursorBlinkTime property typo (bug #5488). Patch by Jérôme.
And fixed in the 4.6 branch as well. The next bugfix release should have it.