This test was run on 1.3.23 version. Server machine is in GMT+2 timezone, client machine is in GMT-7. Here's example demo.
Test app by clicking on proper buttons.
The test was made at 8:00 (GMT+2) As previously said, when testing on server's browser evething is ok, when testing on GMT-7 machine PrevDate returns Aug 28 2009 (from Aug 30 2009) and NextDate returns the same date all the time (Aug 30 2009).
For best results, use the Firefox browser..