Updating Button's background_color not reflected on the UI sometimes - kivy

Question

Well, I'm creating a Kivy app in which you can select only one of many statuses. Every status has his own Button and the selected status has a different background_color from the others.
The problem is that sometimes (apparently random) after clicking a button, two of them stays with his background changed at the same time. The strange thing is that I'm checking the background_color of those elements and it doesn't match with the result that I'm seeing on the screen.
So, the background_color property has one color but another one is being rendered on the screen.
Relevant kv file section:
<StatusButtonsContainer>:
cols: 2
spacing: 8
padding: 0,16,0,0
<StatusButton>:
selected: False
text: self.status_name
on_release: app.on_change_status_click(self.status_name)
font_size: '16'
background_color: self.back_color if self.selected else (0.259, 0.259, 0.259,1)
background_normal: ''
background_down: ''
background_disabled_normal: ''
This is how I'm creating the Button widgets dinamically:
class StatusButtonsContainer(GridLayout):
def __init__(self, **kwargs):
super(StatusButtonsContainer, self).__init__(**kwargs)
for name, color in config.statuses.items():
button = StatusButton(status_name=name, back_color=color)
self.add_widget(button)
class StatusButton(Button):
status_name = StringProperty()
back_color = ListProperty()
And this the function that is executed when the button is pressed:
class ControlsScreen(Screen):
def change_selected_status(self, status):
for button in self.ids.buttons_container.children:
if button.status_name == status:
button.selected = True
button.disabled = True
print('Status ' + button.status_name + ' was selected.')
print('background_color:' + str(button.background_color))
else:
button.selected = False
button.disabled = status in ['printing', 'preparing', 'paused']
print('Status ' + button.status_name + ' was NOT selected.')
print('background_color:' + str(button.background_color))
It's even more weird that this is happening on a Raspberry Pi 3 with Raspbian, but I'm not able to reproduce it on a Windows machine... I double checked that the [input] section in the config is correct and the buttons are being pressed only once.
Versions
Python: 3.6.0
OS: Raspbian GNU/Linux 9 (stretch)
Kivy: 1.10.1

Answer 1

Finally, the problem was that I was updating the UI in a thread different from the main thread.
In my application, the button status can be changed either from the UI directly or from a web socket message. So, when the button's background_color was changed through web socket, the UI update was called by another thread and, for some reason, that was causing the issue.
I've solved it with the #mainthread decorator:
#mainthread
def change_status_ui(self, status):
self.get_screen('Controls').change_selected_status(status)
self.get_screen('Status').change_status(status)
Now, it doesn't matter which thread call this method, it will be executed on the main thread.