OVF info washed out in sunlight

Yesterday I went out with my XPro 1 to do some comparative shots with some adaptive lenses. When I looked through the OVF I could not see the bright frame, guide lines, info, etc. They were there, but were washed out in the sunlight. However, the info could be seen indoors. So, I put on the XF 35/2 and behold the info was all there (outside that is - in the sunlight). I put the three legacy lenses with two different adapters went outside and everything disappeared once again.
The question is...

OVF info washed out in sunlight