не всплывает DropDown в kivy на Линукс

Решил поизучать kivy на примере Живой поиск kivy. Приложение сильно тупит, зависает во время живого поиска по базе данных

Но у меня не всплывает DropDown - просто не появляется

import kivy

from kivy.app import App
from kivy.uix.textinput import TextInput
from kivy.uix.widget import Widget
from kivy.uix.dropdown import DropDown
from kivy.uix.button import Button
from kivy.clock import Clock, _default_time as time
from kivy.properties import ListProperty

from multiprocessing.dummy import Pool # threads
from threading import Semaphore
import sqlite3

MAX_TIME = 1/60.

class TestApp(App):

    data_items = []
    data_sema = Semaphore(1)

    def on_start(self):
        self.threadpool = Pool(1)
        self.db = self.threadpool.apply(sqlite3.connect, ('tikers.db',))
   
    def on_data(self, data):
        print('on_data')
        dropdown = DropDown()
        dropdown.bind(on_select=lambda instance, x: setattr(textinput, 'text', x))
        dropdown.clear_widgets()

        for line in data:
            button = Button(text=line)
            button.bind(on_press=lambda btn: dropdown.select(btn.text))
            dropdown.add_widget(button)
        
        dropdown.open(self.textinput)



    def get_data(self, text):
        print('get_data', text)
        c = self.db.cursor()
        
        self.data_sema.acquire(blocking=True)
        for row in c.execute('SELECT text FROM tiks WHERE text like ?', ( "%"+text+"%" ,)):
            print(row)
            App.get_running_app().data_items.append(row[0])
        self.data_sema.release()
        c.close()
        print('end get_data')

   
    def on_text(self, instance, value):
        print('on_text', instance, value)

        if value:
            self.threadpool.apply_async(self.get_data, (value,),error_callback=print)

    
    
    def consume(self, *args):
        if self.data_items and time() < (Clock.get_time() + MAX_TIME):
             print('consume')
             self.data_sema.acquire(blocking=True)
             self.on_data(self.data_items)
             self.data_items.clear()
             self.data_sema.release()

    
    
    def build(self):
        Clock.schedule_interval(self.consume, 0)
        textinput = TextInput(text='', multiline=False)
        textinput.bind(text=self.on_text)
        self.textinput = textinput
        return textinput

if __name__ == '__main__':
    TestApp().run()