Draggable (borderless)

main.py

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.label import Label

from kivy.core.window import Window

#Window.size = (500, 300)
Window.borderless = True


KV = """
MyLabel
    text: '123456'

"""
class MyLabel(Label):

    def on_touch_down(self, touch):

        self.mouse_pos = Window.mouse_pos
        self.w_left= Window.left
        self.w_top= Window.top

        self.new_left = Window.left
        self.new_top = -Window.top

        self.last_x = self.mouse_pos[0]
        self.last_y = self.mouse_pos[1]

        super().on_touch_down(touch)

    def on_touch_move(self, touch):

        self.new_left += Window.mouse_pos[0]-self.last_x
        self.new_top += Window.mouse_pos[1]-self.last_y

        Window.left = self.new_left
        Window.top = -self.new_top

        super().on_touch_move(touch)

class MyApp(App):
    def build(self):
        self.root = Builder.load_string(KV)


MyApp().run()