I get the answer. Thanks to Kyle.Thomas who posts his answer on https://community.oracle.com/thread/3527282?start=0&tstart=0
It only appears to be an issue when I have the:
<af:panelTabbed id="pt1">
within
<af:panelGridLayout id="pgl1">
<af:gridRow marginTop="5px" height="auto" id="gr1">
<af:gridCell marginStart="5px" width="auto" id="gc1">
solved Oracle ADF: 12c Unresponsive Script (core-ABRAMS-3160.js)