Fix single-click and double-click in the graph view (#8474)

### Related

<!--
Include links to any related issues/PRs in a bulleted list, for example:
* Closes #1234
* Part of #1337
-->

* Closes #8437
* Closes #8442

### What

This implements:
* Single-click on empty space to select view.
* Double-click on node to select entire entity.

Merging @emilk's recent changes (#8469 and #8457) seems to have fixed
the flickering on selection too.

crates/viewer/re_view_graph/src/ui/draw.rs

@@ -362,11 +362,6 @@ pub fn draw_graph(
 
                 let instance_path =
                     InstancePath::instance(entity_path.clone(), instance.instance_index);
-                ctx.handle_select_hover_drag_interactions(
-                    &response,
-                    Item::DataResult(query.view_id, instance_path.clone()),
-                    false,
-                );
 
                 response = response.on_hover_ui_at_pointer(|ui| {
                     list_item::list_item_scope(ui, "graph_node_hover", |ui| {
@@ -383,6 +378,21 @@ pub fn draw_graph(
                     });
                 });
 
+                ctx.handle_select_hover_drag_interactions(
+                    &response,
+                    Item::DataResult(query.view_id, instance_path.clone()),
+                    false,
+                );
+
+                // double click selects the entire entity
+                if response.double_clicked() {
+                    // Select the entire entity
+                    ctx.selection_state().set_selection(Item::DataResult(
+                        query.view_id,
+                        instance_path.entity_path.clone().into(),
+                    ));
+                }
+
                 response
             }
             Node::Implicit { graph_node, .. } => {

crates/viewer/re_view_graph/src/view.rs

@@ -19,7 +19,7 @@ use re_view::{
     view_property_ui,
 };
 use re_viewer_context::{
-    IdentifiedViewSystem as _, RecommendedView, SystemExecutionOutput, ViewClass,
+    IdentifiedViewSystem as _, Item, RecommendedView, SystemExecutionOutput, ViewClass,
     ViewClassLayoutPriority, ViewClassRegistryError, ViewId, ViewQuery, ViewSpawnHeuristics,
     ViewState, ViewStateExt as _, ViewSystemExecutionError, ViewSystemRegistrator, ViewerContext,
 };
@@ -206,6 +206,12 @@ Display a graph of nodes and edges.
             }
         });
 
+        if resp.clicked() {
+            // clicked elsewhere, select the view
+            ctx.selection_state()
+                .set_selection(Item::View(query.view_id));
+        }
+
         // Update blueprint if changed
         let updated_rect_in_scene =
             blueprint::components::VisualBounds2D::from(ui_from_world.inverse() * rect_in_ui);