Editor often freezes within node-editor

Hi, no matter what node-Editor I am using. Blueprint, Material etc. It often freezes. Even if I use only 3 nodes, it already happened to me when using only one node. Just playing around with the settings and the editor freezes and I can not even kill it anymore. No matter how long I wait, even after 30minutes nothing happens anymore. Only when I kill -9 it and restart unreal-engine, I can use it again.