Automatically expand a resource after creating it in the inspector

This reduces the number of mouse clicks needed to set up various nodes,
such as MeshInstance3D and GPUParticles3D.

This is only effective if Open Resources in Current Inspector is enabled
in the editor settings (which is the default).

editor/editor_properties.cpp

@@ -2974,7 +2974,7 @@ void EditorPropertyResource::_set_read_only(bool p_read_only) {
 	resource_picker->set_editable(!p_read_only);
 }
 
-void EditorPropertyResource::_resource_selected(const Ref<Resource> &p_resource, bool p_inspect) {
+void EditorPropertyResource::_resource_selected(const Ref<Resource> &p_resource, bool p_inspect, bool p_force_open) {
 	if (p_resource->is_built_in() && !p_resource->get_path().is_empty()) {
 		String parent = p_resource->get_path().get_slice("::", 0);
 		List<String> extensions;
@@ -2992,7 +2992,10 @@ void EditorPropertyResource::_resource_selected(const Ref<Resource> &p_resource,
 	}
 
 	if (!p_inspect && use_sub_inspector) {
-		bool unfold = !get_edited_object()->editor_is_section_unfolded(get_edited_property());
+		bool unfold = p_force_open;
+		if (!unfold) {
+			unfold = !get_edited_object()->editor_is_section_unfolded(get_edited_property());
+		}
 		get_edited_object()->editor_set_section_unfold(get_edited_property(), unfold);
 		update_property();
 	} else {

editor/editor_properties.h

@@ -674,7 +674,7 @@ class EditorPropertyResource : public EditorProperty {
 	EditorInspector *sub_inspector = nullptr;
 	bool opened_editor = false;
 
-	void _resource_selected(const Ref<Resource> &p_resource, bool p_inspect);
+	void _resource_selected(const Ref<Resource> &p_resource, bool p_inspect, bool p_force_open = false);
 	void _resource_changed(const Ref<Resource> &p_resource);
 
 	void _viewport_selected(const NodePath &p_path);

editor/editor_resource_picker.cpp

@@ -129,7 +129,7 @@ void EditorResourcePicker::_resource_selected() {
 		return;
 	}
 
-	emit_signal(SNAME("resource_selected"), edited_resource, false);
+	emit_signal(SNAME("resource_selected"), edited_resource, false, false);
 }
 
 void EditorResourcePicker::_resource_changed() {
@@ -353,7 +353,7 @@ void EditorResourcePicker::_edit_menu_cbk(int p_which) {
 
 		case OBJ_MENU_INSPECT: {
 			if (edited_resource.is_valid()) {
-				emit_signal(SNAME("resource_selected"), edited_resource, true);
+				emit_signal(SNAME("resource_selected"), edited_resource, true, true);
 			}
 		} break;
 
@@ -483,6 +483,12 @@ void EditorResourcePicker::_edit_menu_cbk(int p_which) {
 			Ref<Resource> old_edited_resource = edited_resource;
 			edited_resource = Ref<Resource>(resp);
 			_resource_changed();
+
+			if (edited_resource.is_valid() && bool(EDITOR_GET("interface/inspector/open_resources_in_current_inspector"))) {
+				// Expand newly created resources, as the user will most likely want to change at least one property within the resource.
+				// This is disabled when resources are forcibly opened in a new inspector, as it would be too intrusive.
+				emit_signal(SNAME("resource_selected"), edited_resource, false, true);
+			}
 		} break;
 	}
 }
@@ -814,7 +820,7 @@ void EditorResourcePicker::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "editable"), "set_editable", "is_editable");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "toggle_mode"), "set_toggle_mode", "is_toggle_mode");
 
-	ADD_SIGNAL(MethodInfo("resource_selected", PropertyInfo(Variant::OBJECT, "resource", PROPERTY_HINT_RESOURCE_TYPE, "Resource"), PropertyInfo(Variant::BOOL, "inspect")));
+	ADD_SIGNAL(MethodInfo("resource_selected", PropertyInfo(Variant::OBJECT, "resource", PROPERTY_HINT_RESOURCE_TYPE, "Resource"), PropertyInfo(Variant::BOOL, "inspect"), PropertyInfo(Variant::BOOL, "force_open")));
 	ADD_SIGNAL(MethodInfo("resource_changed", PropertyInfo(Variant::OBJECT, "resource", PROPERTY_HINT_RESOURCE_TYPE, "Resource")));
 }