Consider the following window constellation with grouping by application enabled: `| (2) Thunar | Mousepad |` If the Mousepad window is active, I can scroll _up_ to reach one of the Thunar windows, but not the second one. If I then scroll _down_, I will reach the second Thunar window, but then I cannot escape the group anymore. Any further scrolling down just switches back and forth between the two windows of the Thunar group. Package version: - xfce4-panel 4.18.0 #691 might be related to this.