Unreal X-Editor is the best tool for programming using Unreal Script language. Enterly developped for Unreal Script and Unreal Developpment Kit, all is here to help the programmer and the game designers ! Auto-complete, class view, find functions in all files, and "Wizards" to create custom weapons, pawns and other objects, or tweak the editor to use DX11 or change sounds,… there are a lot of functions very helpful. you can see all of this on the website, there are many other things to see!