Propagate "quit" event, do not just terminate application. Resize: flag widgets to be resized, do resizes only once before draw. Draw: flag widgets to be redrawn, do not draw everything on any event.
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import locale
locale.setlocale(locale.LC_ALL, '')
from tuikit import Application, Window, Label, AnchorLayout, VerticalLayout
class MyApplication(Application):
    def __init__(self):
        Application.__init__(self, top_layout=AnchorLayout)
        self.top.add_handler('keypress', self.on_top_keypress)
        win = Window(inner_layout=VerticalLayout)
        win.resize(30,10)
        win.title = 'styles'
        for attr in ['blink', 'bold', 'standout', 'underline']:
            label = Label(attr)
            label.color = 'test-' + attr
            win.add(label)
        self.top.add(win)
    def apply_theme(self):
        Application.apply_theme(self)
        self.driver.defcolor('test-blink',              'cyan on blue, blink')
        self.driver.defcolor('test-bold',               'cyan on blue, bold')
        self.driver.defcolor('test-standout',           'cyan on blue, standout')
        self.driver.defcolor('test-underline',          'cyan on blue, underline')
    def on_top_keypress(self, ev):
        if ev.keyname == 'escape':
            self.terminate()
            return True
if __name__ == '__main__':
    app = MyApplication()
    app.start()