Fixing bug 192309, event dialog had a tab named "New Event", I've changed it to just "Event", since it didn't make sense when editing.

calendar/locales/en-US/chrome/calendar/calendar.dtd

@@ -94,7 +94,7 @@
 <!ENTITY newevent.endtime.tooltip    "Choose an end time for this event" >
 <!ENTITY newevent.starttimeerror.alertmessage "Your event cannot end before it has started. Please fix either the start time or the end time." >        
 <!ENTITY newevent.recurendtimeerror.alertmessage "Your event's repeat time cannot be before the event end time. Please fix this, or disable repeating." >
-<!ENTITY newevent.newevent.tab.label "New Event" >
+<!ENTITY newevent.newevent.tab.label "Event" >
 <!ENTITY newevent.recurrence.tab.label "Recurrence" >
 <!ENTITY newevent.contacts.tab.label "Contacts" >
 <!ENTITY newevent.files.tab.label "Files" >