Reason you don't get a colorbox for the form is that it is not configured for the theme. In fact it requests a link to the password page instead by overriding the plugin options. Find printUserLogin_out("[*]", "", 0) in the Zenpage theme's sidebar.php and change the 0 to 2 to always get a colorbox or remove the last parameter to let the plugin option set it.

Ok great, thanks a lot for your time. That resolves the issue.

just out of curiosity i saw that the older version sidebar.php, the default setting was 2. Any special reason for setting it to 0 by default in 1.4.7?

The reason was bascially that the pure link to the password page is "cleaner" and doesn't require the colorbox scripts being loaded on every page. That it does if you use it for the login form overriding the colorbox plugin settings (which I forgot earlier).

ok. thanks a lot. have a great day.