[grouping info] Grouping info stacktrace hard to match to main stacktrace

[lobsterkatie]

In this event, all but one frame is being ignored for grouping because of the customer's stacktrace rules. The frame which is used is the third one from the top:

Locating that frame in the main stacktrace is a little tough, though, because:

• the frame is greyed out and collapsed by default,
• it's at the bottom of the stacktrace, not the top (as it is in the grouping section; this is covered in [grouping info] Reverse stacktrace frame order #81933), and
• unless you click Full Stacktrace or Show 2 More Frames, it's the last frame, not third to last,

all of which together makes for a somewhat confusing experience.