No mouse pointer w/o inputtrap

When I build up my hand-rolled Photon startup script and manually launch
devi-hirun (with identical parameters to what inputtrap picks), I get no
mouse cursor on the resulting display. If, on the other hand, I omit the
devi-hirun command and instead call inputtrap, it launches devi-hirun but
also gives me a mouse cursor!

Using phin -A, I can see that the difference between these two sessions is
that devi-hirun’s Photon region has the Ph_PTR_REGION flag set when
inputtrap launches it, but not when I launch it directly from script.

What am I missing?

– Kevin