window-management: prevent dragging the root container

src/ifs/wl_seat/pointer_owner.rs

@@ -1137,6 +1137,9 @@ impl SimplePointerOwnerUsecase for WindowManagementUsecase {
         let (mut dx, mut dy) = pos.translate(x, y);
         let owner: Rc<dyn PointerOwner> = if button == BTN_LEFT {
             if let Some(tl) = pn.clone().node_into_toplevel() {
+                if tl.tl_data().is_root_container() {
+                    return false;
+                }
                 seat.pointer_cursor.set_known(KnownCursor::Move);
                 if tl.tl_data().is_fullscreen.get() {
                     Rc::new(ToplevelGrabPointerOwner {
@@ -1578,6 +1581,10 @@ impl UiDragUsecase for TileDragUsecase {
     }
 
     fn apply_changes(&self, seat: &Rc<WlSeatGlobal>) -> Option<Rect> {
+        if self.tl.tl_data().is_root_container() {
+            self.destination.take();
+            return None;
+        }
         let (x, y) = seat.pointer_cursor.position();
         let dest = seat.state.root.tile_drag_destination(
             self.tl.node_id(),

src/tree/toplevel.rs

@@ -918,6 +918,13 @@ impl ToplevelData {
         }
         NodeLayerLink::Tiled
     }
+
+    pub fn is_root_container(&self) -> bool {
+        let Some(parent) = self.parent.get() else {
+            return false;
+        };
+        parent.node_is_workspace()
+    }
 }
 
 impl Drop for ToplevelData {