Fix Alt-clicking the node already feeding the output blanking all the artwork (#4708)

Author: Keavon

editor/src/messages/portfolio/document/utility_types/network_interface/characterization_tests.rs

@@ -1353,15 +1353,15 @@ async fn toggle_preview_transitions_with_a_connected_export() {
 	assert_eq!(export_node(network_interface), Some(artboard));
 	assert_eq!(network_interface.previewing(&[]), Previewing::No);
 
-	// Toggling the restore node while previewing promotes it to the export with nothing left to restore
+	// Toggling the restore node while previewing ends the preview by restoring it
 	network_interface.toggle_preview(node, &[]);
 	network_interface.toggle_preview(artboard, &[]);
 	assert_eq!(export_node(network_interface), Some(artboard));
-	assert_eq!(network_interface.previewing(&[]), Previewing::Yes { root_node_to_restore: None });
+	assert_eq!(network_interface.previewing(&[]), Previewing::No);
 
-	// Toggling it once more ends the preview by disconnecting the export entirely
+	// Toggling the node already feeding the export changes nothing
 	network_interface.toggle_preview(artboard, &[]);
-	assert_eq!(export_node(network_interface), None);
+	assert_eq!(export_node(network_interface), Some(artboard));
 	assert_eq!(network_interface.previewing(&[]), Previewing::No);
 
 	assert_invariants(&editor, "after cycling through the preview states");

editor/src/messages/portfolio/document/utility_types/network_interface/mutations.rs

@@ -1291,8 +1291,13 @@ impl NodeNetworkInterface {
 						new_export = root_node_to_restore.map(|root_node| root_node.to_connector());
 						new_previewing_state = Previewing::No;
 					}
-					// The export is clicked and there is no preview
+					// The export is clicked and there is no preview, so it already shows the primary output a preview would
+					else if previous_output_index == 0 {
+						return;
+					}
+					// The export is clicked and there is no preview, but it comes from another output, so preview the primary one and restore that afterward
 					else {
+						new_export = Some(OutputConnector::primary_output(toggle_id));
 						new_previewing_state = Previewing::Yes {
 							root_node_to_restore: Some(RootNode {
 								node_id: previous_export_id,
@@ -1309,10 +1314,10 @@ impl NodeNetworkInterface {
 					if let Previewing::Yes { root_node_to_restore } = self.previewing(network_path) {
 						// There is also a solid line being drawn
 						if let Some(root_node_to_restore) = root_node_to_restore {
-							// If the node with the solid line is clicked, then start previewing that node without restore
+							// If the node with the solid line is clicked, then end the preview by restoring it
 							if root_node_to_restore.node_id == toggle_id {
-								new_export = Some(OutputConnector::primary_output(toggle_id));
-								new_previewing_state = Previewing::Yes { root_node_to_restore: None };
+								new_export = Some(root_node_to_restore.to_connector());
+								new_previewing_state = Previewing::No;
 							} else {
 								// Root node to restore does not change
 								new_previewing_state = Previewing::Yes {