Created attachment 7270 Patch for scrolling through open windows The feature where you can scroll through the windows with the mouse wheel doesn't work anymore. What needs to happen is gtk_widget_add_events (GTK_WIDGET(child->button), GDK_SCROLL_MASK | GDK_SMOOTH_SCROLL_MASK); must be called so the scroll event is actually recognized. Even then it still doesn't work if you use Smooth Scrolling, there's a TODO at that line. I have provided a patch which takes care of these issues.
Created attachment 7273 That patch contained an error in itself, here's the final version
Stefan Berzl referenced this bugreport in commit c2fc42eb5debd536bdce6761eb685ac65e6335c8 tasklist: Fix scrolling to cycle through open windows (Bug #13789) https://git.xfce.org/xfce/xfce4-panel/commit?id=c2fc42eb5debd536bdce6761eb685ac65e6335c8
Successfully tested and pushed. Thanks for the patch!