A new feature of Oracle JRE 1.7.0_51 is that self-signed and unsigned applets are completely blocked at High (the default value) on the Security Slider:
This means that applets in WebGUI such as the Active Event List, Event Dashboard and maps, which previously launched, although with security warnings, now will not launch at all in the current GA builds 220.127.116.11 and 18.104.22.168.
The WebGUI team is aware of this problem and have released a test fix and instructions for two workarounds. The first workaround involves lowering the Security Slider. The second involves adding the WebGUI context to the new Exception Site List. The flash is here.
The APAR for the test fix is IV51526. Customers should request the fix by opening a PMR with Technical Support. Please note also that the test fix is compatible with 22.214.171.124 or 126.96.36.199 only. If your installation is on an earlier build, you will need to apply the relevant fix pack before taking the test fix. Also, if you are already at this test fix level and have additional test fixes applied, you will need to notify Support of your version string so that your existing test fixes can be rebuilt with IV51526.