Valve Developer Community wiki states, that
"Insurgency is based on Counter-Strike: Global Offensive's engine branch."
So I dragged CSGO's Hammer++ version into Insurgency's bin folder with original Hammer (Insurgency has SDK in game files by default), loading circle on my mouse pointer appeared and thats it. How many times I launched Hammer++, it just shows loading circle for a few seconds and do nothing.
I tried different versions of Hammer++, but they don't work either, they just throw error as if I launched Hammer++ exe from desktop, like it can't find required files
Any ideas what can cause this and how to fix it?