Thanks for your post.
Unfortunately SQL Compare doesn't display a difference if the trigger is enabled on one database and not on another.
Displaying the difference in trigger status is currently on the wishlist for SQL Compare, and will hopefully be added to a future version. The feature tracking code for this is SC-3996.
As a workaround, you can query the status of all triggers on a database using the following:
SELECT T.[name] as TableName, TR.[Name] as TriggerName,
CASE WHEN 1=OBJECTPROPERTY(TR.[id], 'ExecIsTriggerDisabled')THEN 'Disabled' ELSE 'Enabled' END Status
FROM sysobjects T INNER JOIN sysobjects TR on t.[ID] = TR.parent_obj WHERE (T.xtype = 'U' or T.XType = 'V')
AND (TR.xtype = 'TR') ORDER BY T.[name], TR.[name]
I hope this is helpful.