We're experimenting with making particularly useful milestones available as releases. 5.0b2 is now available on the openlaszlo.org website under Nightly builds. See: http://www.openlaszlo.org/download
5.0b2 is a milestone towards 5.0 and contains significant bug fixes that may be useful to you. It is NOT fully tested nor is it a qualified or recommended release. It is, however, a milestone that focuses on DHTML bugs and you may find it useful in your development.
You can review the bug fixes here: http://wiki.openlaszlo.org/5.0b2_Release_Notes