Remove button from button_group when free

scene/gui/base_button.cpp

@@ -539,15 +539,15 @@ BaseButton::BaseButton() {
 	set_focus_mode(FOCUS_ALL);
 	enabled_focus_mode = FOCUS_ALL;
 	action_mode = ACTION_MODE_BUTTON_RELEASE;
+}
+
+BaseButton::~BaseButton() {
 
 	if (button_group.is_valid()) {
 		button_group->buttons.erase(this);
 	}
 }
 
-BaseButton::~BaseButton() {
-}
-
 void ButtonGroup::get_buttons(List<BaseButton *> *r_buttons) {
 
 	for (Set<BaseButton *>::Element *E = buttons.front(); E; E = E->next()) {