Fix root-thread action-menu bug
Fix root-thread action-menu bug

The action-menu can appear when a form has already been created below
the root thread; this makes it possible to open e.g. 2 edit-forms (for
the root post only). Prevent this.

debiki/debiki-server-old,debiki/debiki-server-old,debiki/debiki-server-old,debiki/debiki-server-old