UMG editor crashes UE 4.9

Anytime I click the background of the umg editor and move my mouse, the whole engine crash. Everytime. on 4.9

Hi heartlessphil,

Please post this to the answerhub in the bug reports section (link in signature). Please include your callstack, crash logs (\Unreal Projects\PROJECTNAME\saved\logs), and any steps you are taking to reproduce this. Additionally, please make sure to include whether or not this occurs in a clean, blank project with no additional content or if this is limited to one project.