This is a good suggestion that I think might be worth pursuing. Some thoughts:

It would be easy to have it autopopulate the bug field with the last bug you filed. In fact, at the moment, the bug modal actually explicitly clears the last bug you filed from the input when you open a new one. This was done to prevent confusion/accidentally linking the same bug too many times, so we'd have to see if it's generally desirable to have the form "remember" your last input. 

I like the idea of having the bug modal show a list of the last several bugs linked with titles though I think this would be a medium amount of work to implement and probably lower priority than other things. One thing I realized is that adding bulk alert actions is on the roadmap to be added soon, and I think this might help with the pain of having to link the same bug over and over again. Bug for bulk actions here: https://bugs.chromium.org/p/chromium/issues/detail?id=717713 

To clarify: is the problem that you see multiple alerts for "amd64-generic-telemetry" *at the same time* in /gardener? Or that you see alerts for "amd64-generic-telemetry" come and go frequently over time?

amd64-generic-telemetry is broken. It cycles every hour or two, and I get a new alert saying it is broken. I'd like to associate the later breakages with the bug I created for the initial break.

Maybe that's part of the grouping feature? I didn't try that - I wasn't sure what it meant when I saw the button in the UI.