Override an engine class function

Is it possible to override engine class functions without having to download the entire engine / compiling it?

I have modified ‘Editor/GraphEditor/SGraphPanel.cpp’ ‘OnMouseMove’ function for instance. Having to compile the entire engine for this tiny change is a huge hassle. I tried doing ‘Add C++ Class’ within the editor but could not find SGraphPanel in the list. The closest I found was the EdGraph.