Can not delete invalid message PostEvent

[andreas andreas]

PostEvent of Beliefset,

when we press '+' addition button, we will get an empty record. We can not use 'x' delete button in the widget to delete those empty record. (Actually a null-pointer exception is thrown out (but not seen by users, we can see it if we deploy the plugin from an RCP development environment and look at the console output), this is due to inability to access the message that should be pointed by PostEvent.)

Solved. (added the phase to detect the validity of message before trying to delete it.)