What did you do to get the error?

Note that there are some problems with the javascript in 1.0.0a2. The comment delimiters were wrong. This has been fixed.

I think I got the similar problem. Noticed it in both 1.0.0a2 and 1.0.0a3, with the $g_dhtml_filters set to ON.

The Javascript error pops-up when I tried to select an option in the drop-down list (any, none, between, etc) of a Date custom field. (see screenshot custom_field_date_filter_error.jpg)

I've tested using the Opera 8 browser too and from the Javascript console, this is the error message:

http://localhost/mantis/view_all_bug_page.php
Event thread: change
Error:
name: ReferenceError
message: Statement on line 1: Reference to undefined variable: toggle_custom_date_field_3_controls
Backtrace:
Line 1 of script
toggle_custom_date_field_3_controls();
At unknown location
[statement source code not available]

If I set the DHTML filter set to OFF, then the error doesn't appear.

The script code that switches the filter display on and off is missing from the dhtml filter view.

Fixed in CVS. Javascript code to manage the date boxes was not loading properly.

core/filter_api.php -> 1.116