Agranite

You get use to it. I use a Logitech G502 on my home PC, and I use a spare Razer Naga (2014) on my gaming laptop. I need a minimum of 3 programmable thumb button to bind to shift/ctrl/alt =) I also have two Logitech G13 as well. I was going to get the razer version, but after how much I don't like razer driver causing problems, i decided against it. I actually want to try out the MadCatz gaming mouse, but for a mouse, it's pretty pricey.

Blade & Soul is power by Unreal Engine 3, and should support mouse thumb button 1 & 2 keybind, so I have no idea why is not supported. If you look at all the documentations, all UDK, UE3.5, UE4 game engine has support for it. Here's some food for thought though. Most game don't support buttons other than LMB, RMB, MMB, TMB1, TMB2 is for the same reason with gamepad in the past. Every devices uses different code/data to interpret the mouse button press, which is why there is some effort to collect data on how every mouse manufacture does it. You will not see naive support for it until Microsoft creates an API Standard for mouse buttons and encourage all peripheral manufacture to start following it, the same way they created the X-Input API for gamepad controllers that all current game developer started using. EDIT: If GameGuard is closing your game because your mouse game profiler checks the process for its id, then remove the auto-profile feature from the mouse profile and have it run in persistent mode. (This does not apply to Razer. I've always hated Razer Synapse drivers. They like to cause other drivers to crash, for example if you have both a Logitech and Razer product connected to the computer, Razer driver will cause Logitech driver to crash. Whether it's Logitech, SteelSeries, Corsair, Razer, and many other brands, I've use them all and Razer Synapse causes the most problems.)