Latitude E7490 touchpad right button not working

hi guys,

on my dell latitude E7490, from a few days the right button on the touchpad (not the pointstick one), is not responding or doing any action.

i tried one of those websites and tools that highlight what button is firing up and something strange happening.

when i click the left button on the touchpad, the center button fires up (however it left clicks fine)
right button, nothing happening, it "clicks" fine however

tried

uninstall reinstall mouse drivers
safe mode

external mouse of course works

any thoughts? hardware problem? touchpad gestures work, scrolling, 2 fingers for right-click... so i can do everything but still not ideal.

thanks,
Gab