Editor Color Picker Disappears in Niagara Curve BUG Color Picker BROKEN

I dont know how this happend. The last thing i done enabled the raytracing in project settings. After restart and recompile the whole project and some crashes. I wanted to work again with my Niagara Setup. But suddenly i cannot select a Color in Niagara Particles via Curve Parameter. if double clicked nothing happen. When i click right _> Choose Color. The Window appears for a sec and then disappears again. I tried a new EMPTY (without raytracing) Project with 4.26. Same behavior. I tried to restart/uninstall /Verify the Install Still the same Problem. In Version 4.25. the Color picker works… I dont know what to do, i have to get the color picker there… What can cause the Problem?

Here you can see the Problem. Niagara Color Picker BUG - YouTube