GTK3 breeze theme treeview separator bug

treeview.py

#
# This example treeview reproduces the treeview glitching with the gtk-breeze theme
# under GTK 3.22 (Fedora 25)
#

import gi
gi.require_version("Gtk", "3.0")
from gi.repository import Gtk


window = Gtk.Window.new(Gtk.WindowType.TOPLEVEL)
window.connect('destroy', Gtk.main_quit)

tv = Gtk.TreeView.new()

tv.append_column(Gtk.TreeViewColumn('col1', Gtk.CellRendererText(), text=0))
tv.append_column(Gtk.TreeViewColumn('col2', Gtk.CellRendererText(), text=1))

model = Gtk.TreeStore.new([str, str])

row1 = model.append(None, ['r11', 'r12'])
model.append(row1, ['c1-1', 'c1-2'])

model.append(None, [None, None])

row2 = model.append(None, ['r21', 'r22'])
model.append(row2, ['c2-1', 'c2-2'])
model.append(row2, ['c3-1', 'c3-2'])

tv.set_model(model)

# If you comment this out, the bug goes away
tv.set_row_separator_func((lambda m, i: m.get_value(i, 1) is None))

window.add(tv)
window.show_all()

Gtk.main()