Hi Edward,
Hm, it works with the latest EyeX Engine. I have a vague memory that we had an engine version where this state path and a number of other state paths that have been deprecated accidentally didn’t work, but it was fixed in the following engine release. Which version of the EyeX Engine are you using?
Anyway, as described in the Readme for the 1.5 SDK that state path has been deprecated and you should use TX_STATEPATH_EYETRACKINGSCREENBOUNDS instead, on EyeX Engine 1.3.0 and higher.