[ptx] hugin bug - Optimiser custom parameters

[Bruno Postle]

If I select "the custom parameters below" in the hugin "optimizer" 
tab, I can select check boxes and optimise individual parameters.

This is ok with "Image Orientation" parameters, but "Lens 
Parameters" behave differently.  After I optimise they always get 
reset to 'unchecked', so I have to keep reselecting them again and 
again which I guess makes this a bug.

-- 
Bruno