A colleague just told me that you of course can just use the Query Bar in the top to filter the entire page to just show one transaction/trace. That way you don't have to mess around with the URL.
E.g if you want to see the span waterfall for a transaction with the ID 42cdd1306af31b5b, just add the following to the Query Bar:
transaction.id: "42cdd1306af31b5b"
Or if you have the trace id, you could write:
trace.id: "66e024c806473ed1e5ac3d58546d197d"
That will filter the entire view to just that transaction, and by effect therefore auto-select the bucket it is in and show its waterfall:
