Chameleon licking branches and sensing the air

Chameleons have, based on our recent knowedge, very limited sense of olfaction and vomerolfaction...
Though, we can observe them to lick branches with exposing a little bifurcated tip of the tongue few millimeters out of the mouth...
Sometimes they even sense the air...
It seems to be a standard vomerolfaction procedure, as seen by many other squamates.
I have never seen a chameleon doing it and take an action on the result. They seem not to care but they lick the branches and air...
Is it an inherited non-functional atavism or is there any meaning behind?

Furcifer pardalis, Ambilobe, Madagascar                                         Kinyongia multituberculata, W Usambara Mts, Tanzania

Kinyongia multituberculata, W Usambara Mts, Tanzania

Furcifer major, Tulear, Madagascar 

Furcifer willsii, Analamazaotra, Madagascar