Thanks for the feedback, yes, the entire site is done in 100% elm-ui, data endpoints are done in C# REST apis. As far as the slowness, you are right, if you use older browsers, it is slow when you exp/col or even clicking on filter check boxes, I am on Version 71.0.3578.98 (Official Build) (64-bit) and I don’t see any delay at all, just curious how did you get the ~250 ms number ? did you use any tools to measure the delay ?