The 'Force Relative Tex' button in an actor export covers the 'Motion Extraction' button. Changing line 780 in 'chicken_exportR71b.py' from
'self.bForceRelTex.update([w-560, top-1, 150, 20])' to
'self.bForceRelTex.update([w-wPad-660, top-1, 150, 20])',
fixes the overlap.