Sorry, but I totally misunderstood the problem.
"Edit" -> "Find" is meant to select only a single element. "Edit" -> "Find" is meant to be combined with "Edit" -> "Find Next" and "Edit" -> "Find Previous". If there are multiple elements that match Find's criterion, repeated use of Find Next and Find Previous will cycle the selection through all matching elements.
You are right, though, the green start button does not seem to work when docking Find.
If you want to select all matching elements at once, you need to use "Tools" -> "Select Elements". (And Select Elements is the one that was broken and is fixed as of 3.12.1.)