: message: message auto_dismiss: False title: "Error" size_hint: None, None width: grid.width + dp(25) height: grid.height + root.title_size + dp(48) GridLayout: id: grid size_hint: None, None size: self.minimum_size padding: [10, 5] cols: 1 AnchorLayout: anchor_x: "center" anchor_y: "bottom" size_hint: None, None height: message.height width: max(message.width, butt.width) Label: id: message size_hint: None, None size: self.texture_size padding: [10, 5] AnchorLayout: anchor_x: "center" anchor_y: "bottom" size_hint: None, None height: butt.height width: max(message.width, butt.width) Button: id: butt text: 'Close' size_hint: None, None size: self.texture_size padding: [10, 5] on_release: root.error_exit();