refs #134: polygon disappears when selecting another object on scene. (…

…#247)

addons/popochiu/editor/canvas_editor_menu/popochiu_canvas_editor_menu.gd

@@ -142,9 +142,16 @@ func _on_selection_changed() -> void:
 		if PopochiuEditorHelper.is_popochiu_obj_polygon(selected_node):
 			_active_popochiu_object = selected_node.get_parent()
 		elif PopochiuEditorHelper.is_popochiu_room_object(selected_node):
+			var polygon = PopochiuEditorHelper.get_first_child_by_group(
+				_active_popochiu_object,
+				PopochiuEditorHelper.POPOCHIU_OBJECT_POLYGON_GROUP
+			)
+			if (polygon != null):
+				polygon.hide()
+			btn_interaction_polygon.set_pressed_no_signal(false)
 			_active_popochiu_object = selected_node
 		else:
-			_active_popochiu_object =  null
+			_active_popochiu_object = null
 
 	# Case 2:
 	# We have more than one node selected. This can happen because the user selected

addons/popochiu/editor/helpers/popochiu_editor_helper.gd

@@ -193,6 +193,8 @@ static func is_editing_room() -> bool:
 
 # Quick-access functions
 static func get_first_child_by_group(node: Node, group: StringName) -> Node:
+	if (node == null):
+		return null
 	for n in node.get_children():
 		if n.is_in_group(group):
 			return n