Зафиксировать размер Layout

При добавлении новой задачи в ToDo List уменьшается верхний Layout self.topsp = BoxLayout(size_hint=(1, 0.1)) Возможно ли это исправить или реализовать как то по другому?

from kivy.app import App
from kivy.uix.behaviors import button
from kivy.uix.button import Button
from kivy.core.window import Window
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.popup import Popup
from kivy.uix.textinput import TextInput
from kivy.uix.label import Label
from kivy.config import Config
from kivy.core.window import Window
from kivy.event import EventDispatcher
from kivy.uix.checkbox import CheckBox


Window.size = (400, 800)
Window.clearcolor = (1, 1, 1, 1)


class Task (BoxLayout):
    pass

class Text (TextInput):
    pass

class CloseBut(Button):
    def on_press (self):
        app.root.add_widget(Task())

class Quest (Popup):
    def creat (self):
        pass
    
class Plus (Button):
    def on_press (self): 
        pass

class Label (Button):
    pass

def add(self):
    print("you write - " + Text.text)

def open (self):
    q = Quest()
    q.open()



class DaysApp(App):

    def build(self):

        self.mainspase = BoxLayout(orientation='vertical')

        self.topsp = BoxLayout(size_hint=(1, 0.1))
        self.toplsp = BoxLayout(size_hint=(0.75, 1))
        self.toprsp = BoxLayout(size_hint=(0.25, 1))

        self.midsp = BoxLayout()

        self.topsp.add_widget(self.toplsp)
        self.topsp.add_widget(self.toprsp)

        self.mainspase.add_widget(self.topsp)
        self.mainspase.add_widget(self.midsp)

        self.label = Label()
        self.plus = Plus()
        self.pop = Quest()

        self.toplsp.add_widget(self.label)
        self.toprsp.add_widget(self.plus)
                
        self.plus.bind(on_press = self.pop.open)
        
        return self.mainspase



if __name__ == '__main__':
    app = DaysApp()
    app.run()

<Task>:
    size_hint: None, None
    width: 400
    hidth: 50
    Button:
        text:'123'
        background_color: 0, 0, 0, 1
    CheckBox:
        size_hint: .4, 1
        color: 0,1,1,1

<Label>:
    text: "Days"
    background_normal: '2.png'
    background_down: '2.png'

<Plus>:
    text: "+"
    background_normal: '1.png'
    background_down: '2.png'

<CloseBut>:
    background_normal: ''
    background_color: 0, .75, .75, 1
    text: "Add"

<Text>:
    font_size: 16

<Quest>:
    auto_dismiss: True
    title: "Add task"
    title_color: [0,.75,.75,1]
    separator_color: [0,.75,.75,1]
    background: '0.png'
    size_hint: None, None
    size: 350, 350
    BoxLayout:
        orientation:"vertical"
        Text:
            size_hint: 1,1
            text: '1'
        BoxLayout:
            size_hint: 1,.1
        CloseBut:
            size_hint: 1,.2
            on_release: root.creat()