Interesting, I was able to reproduce this (at least with the Whitney Houston page shown, in Chrome 44.0.2403.125).
Only a guess, but I suspect that this issue is specific to Findagrave and cannot be fixed on FamilyEcho's end. It probably has to do with how Findagrave handles frames - the "Click to see X's Website" feature opens a URL inside a browser frame, and something with Findagrave probably isn't playing nice with FamilyEcho's attempt to do this - it immediately wipes out all other frames on the page and just displays a Findagrave page like any other website.
As a short-term workaround, one way to get your tree back is to hold down the back button and skip back two pages - this will prevent Findagrave from automatically redirecting you. (Unfortunately, you'll still have to navigate all over again to the person you were originally looking at in your tree.)