window.opener is null in firefox

You open a window from another domain/subdomain. In this case you don't have access to parent window that opened the target window because security permissions don't allow that.

For example if you open a page of site2.com from a page of site1.com the target window has it's opener null.

If you open a page of site2.site.com from a page of site1.site.com it's also no access because these are two different sites.

But if you a page of site.com page from page of site.com or page of subdomain.site.com from page of site.com you have the access because security permissions allow that.

Note: maybe 'prcsTypeSelectionPopup?event=prcsTypeSelection' is incorrect. Change it to root correct path without domain, for example:

/prcsTypeSelectionPopup?event=prcsTypeSelection

it works only for "parent.window.opener" and not for "window.opener"

Thanks Sergzach for your time