Using thumb mouse buttons when hovering ability choices picks them

[crhicko]

I use Mouse 4 as ptt in discord. When selecting an ability to upgrade, if i press mouse 4 it will select the ability. I would expect just mouse 1 to be able to click on that menu. I'll often accidentally pick an ability when hovering to read them and talking in Discord at the same time (not sure if this happens if the in game PTT button is used in the same case).