Retire deleted saved-view owners after group model removal

crates/oa-desktop/src/app/saved_removal.rs

@@ -250,6 +250,23 @@ impl App {
             Ok(_) => {
                 self.selected_node = None;
                 self.behavior.diagram.placement = None;
+                // A selected machine can own the current saved view. Retire
+                // those UI references only after its transaction succeeds.
+                if self
+                    .behavior
+                    .active_owner
+                    .is_some_and(|id| !self.project().contains(id))
+                {
+                    self.behavior.active_owner = None;
+                }
+                if self
+                    .behavior
+                    .diagram
+                    .diagram
+                    .is_some_and(|id| !self.project().diagrams.contains_key(&id))
+                {
+                    self.behavior.diagram = Default::default();
+                }
                 if self.page == Page::Behavior
                     && let Some(machine) = machine.filter(|id| self.project().contains(*id))
                 {