Logitech g502 dpi shift

[Collda]

I cant seen to work out how the dpi shift works. Ive assigned two different dpis to default and shift.
But when i click the button ive assigned the dpi shift too the dpi doesnt lower.

 

[plaintuts]

The side button at the tip of your thumb

 

[Collda]

But it doesnt lower it

 

[plaintuts]

You need to press and hold