editor plugin

I want to crete editor plugin similar to SpeedTree, where can I draw content in seperate window.

I know that to achieve this I need to use Slate, but anybody have tutorial or links for creating Editor Plugins. With Slate?

This is the best starting point: Extending the Editor

There isn’t much around in the way of written information on working with the editor code, you just need to watch that stream and then start digging through the engine code. Slate in particular is fairly easy to learn by example from the engine editor code. The details of how to hook into various workflows in the editor is harder work.