bz pointed out in bug 407956 that nsTreeBodyFrame::GetCoordsForCellItem calls GetPseudoStyleContext(nsCSSAnonBoxes::moztreerow) immediately after calling GetCellProperties, so that will be getting the -moz-tree-row pseudo with the properties set to those of the cell, rather than that of the row. I don't know of anyone who actually sets row pseudo properties based on the view's properties let alone expects appropriate cell item coordinates.

(I'm feeling slightly under the weather at the moment, so I can't seem to focus on the words long enough to work out what's being talked about, but...) GetCoordsForCellItem has had a comment about this since forever, I think. This is what (2) is about, right? <http://mxr.mozilla.org/mozilla-central/source/layout/xul/tree/nsTreeBodyFrame.cpp#1081> "[T]he bug for this" that the comment refers to is bug 74831. See bug 74831, comment 7.

(In reply to Colby Russell from comment #1) > GetCoordsForCellItem has had a comment about this since forever, I think. > This is what (2) is about, right? > <http://mxr.mozilla.org/mozilla-central/source/layout/xul/tree/ > nsTreeBodyFrame.cpp#1081> No, this is about the tree asking the view for the cell's properties when calculating the row's border/padding in the first place.