Add an editor setting for the 3D selection box color

A restart is required to apply the setting change.

editor/editor_settings.cpp

@@ -521,6 +521,10 @@ void EditorSettings::_load_defaults(Ref<ConfigFile> p_extra_config) {
 	_initial_set("editors/3d/secondary_grid_color", Color(0.38, 0.38, 0.38, 0.5));
 	hints["editors/3d/secondary_grid_color"] = PropertyInfo(Variant::COLOR, "editors/3d/secondary_grid_color", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_DEFAULT);
 
+	// Use a similar color to the 2D editor selection.
+	_initial_set("editors/3d/selection_box_color", Color(1.0, 0.5, 0));
+	hints["editors/3d/selection_box_color"] = PropertyInfo(Variant::COLOR, "editors/3d/selection_box_color", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_RESTART_IF_CHANGED);
+
 	// If a line is a multiple of this, it uses the primary grid color.
 	// Use a power of 2 value by default as it's more common to use powers of 2 in level design.
 	_initial_set("editors/3d/primary_grid_steps", 8);

editor/plugins/node_3d_editor_plugin.cpp

@@ -4574,8 +4574,8 @@ void Node3DEditor::_generate_selection_boxes() {
 
 	Ref<StandardMaterial3D> mat = memnew(StandardMaterial3D);
 	mat->set_shading_mode(StandardMaterial3D::SHADING_MODE_UNSHADED);
-	// Use a similar color to the 2D editor selection.
-	mat->set_albedo(Color(1, 0.5, 0));
+	const Color selection_box_color = EDITOR_GET("editors/3d/selection_box_color");
+	mat->set_albedo(selection_box_color);
 	mat->set_transparency(StandardMaterial3D::TRANSPARENCY_ALPHA);
 	st->set_material(mat);
 	selection_box = st->commit();
@@ -4583,7 +4583,7 @@ void Node3DEditor::_generate_selection_boxes() {
 	Ref<StandardMaterial3D> mat_xray = memnew(StandardMaterial3D);
 	mat_xray->set_shading_mode(StandardMaterial3D::SHADING_MODE_UNSHADED);
 	mat_xray->set_flag(StandardMaterial3D::FLAG_DISABLE_DEPTH_TEST, true);
-	mat_xray->set_albedo(Color(1, 0.5, 0, 0.15));
+	mat_xray->set_albedo(selection_box_color * Color(1, 1, 1, 0.15));
 	mat_xray->set_transparency(StandardMaterial3D::TRANSPARENCY_ALPHA);
 	st_xray->set_material(mat_xray);
 	selection_box_xray = st_xray->commit();