kv = """
<SublimeLauncher>:
    BoxLayout:
        size: root.size
        canvas:
            Color:
                rgb: 1, 0, 0
            Rectangle:
                size: self.size
        orientation: 'vertical'
        spacing: 10
        Label:
            text: "Enter the path to the folder to open. \\nPress OK if you would like to open without a directory"
        TextInput:
            id: folderpath
        Button:
            text: 'OK'
"""
Builder.load_string(kv)
Kivy - базовое приложение имеет странное выравнивание