If you are using IE9 and are using my Xpages Dojo Login Custom Control from OpenNTF.org (or any Dojo dialog), then you should upgrade the control.

Another option would be to simulate IE8 on your xpage, but I'm personally not happy about that.

The built-in dojo workaround voor IE for dojo dialogs does not apply anymore on IE9. The result is a transparent screen, but no dialog.

 

You can fix the issue by upgrading to Dojo 1.6, but that is not a option for many of us. 

I have taken the surrounded function where the fix is applied from this link, entered it into a outputscript and put the outputscript in the custom control.

 

You can download the latest version of the login control here