Recently i had an UWL issue assigned, where the customer was in the portal version 184.108.40.206. The customer the followibg issues in the Chrome and Firefox :
1) UWL work items are not opening.
2) Create Task Button and Tabs (Tasks, Alerts, and Notifications, SAP Office Mails, Tracking,Pririoty Task), Refresh link are not working.
But the same worked fine with Internet Explorer, Its necessary to know about the issue as the new updates should kept in mind when any of you face the similar issue.
1) Mozilla firefox and Chrome is not supported for any Administrative activity as per PAM link:
2) For all end users it is supported from SP9.
3) Updating the portal for 7.4 SP 15 will support the portal in standards mode for Ajax Standards framework page for Admin users also but only for Browser Internet Explorer, but not for other browsers.