Thank you all for comments.
beetleman wrote:What beautiful colors on this dragonfly. Is there a reason for them to park their wings and body in that position?
They do it because they are called Dropwings
No seriously, the most common reason for this should be that the wings trap air around the thorax, though increasing the temperature of especially the wing muscles. That is at least true for a lot of dragonflies in cooler regions, but I think it's the same reason for Trithemis species.
I wondered though if the posture might increase the effective field of view when the dragonfly is perched.
Other dragonflies with large coloured areas at the basal part of the wings, may use these as shades for the thorax and abdomen, as not to overheat in the mid day sun.
Erland