When using the cell edit functionality on a date column in a table, and if that cell has value 0000-00-00, clicking it, results in replacing the value with the current date. The date selector pop up is not displayed (or at least not long enough to see it), not giving the user the chance to choose the date with the selector.
Clicking it again (after 0000-00-00 was replaced by current date f.e. 2012-08-24), displays the date selector popup as expected.
Tested on Windows 7 SP1 x64 with Firefox 14.0.1 and Chrome 21.0.1180.83 m