Transform Layer is constructed with an invalid matrix

[Klu1d]

Question

When I add an instance of the Sec class to the page, I get this error. Why is this happening and how can it be fixed?

Code sample

from flet import (
    Row,
    Column,
    Container,
    Text,
    UserControl,
    border_radius,
    colors,
    icons,
    Icon,
    IconButton,
    ImageFit,
    alignment,
    Tabs, Tab,
    AlertDialog,
    TextField,
    InputBorder,
    TextButton,
    MainAxisAlignment,
    Page,
    app
)

class Sec(UserControl):
    def build(self):

        self.tabs = Tabs(
            animation_duration=300,
            selected_index=0,
            tabs=[
                Tab(text="STORAGE", content=Container(bgcolor='red')),
                Tab(text="FILE", content=Container(bgcolor='blue')),
            ],
            expand=1,
        )
        
        return self.tabs
    

def main(page: Page):

    tol = Sec()
    page.add(tol)

app(target=main)

Error message

[ERROR:flutter/flow/layers/transform_layer.cc(24)] TransformLayer is constructed with an invalid matrix.
[ERROR:flutter/flow/layers/transform_layer.cc(24)] TransformLayer is constructed with an invalid matrix.

------------------------------------------------------

• I have searched for answers to my question both in the issues and in previous discussions.

[FeodorFitsner]

What OS is that?

[FeodorFitsner]

The latest Flet is running fine on Ubuntu 22.04. But I guess I'm running non-Gnome window manager, right?

[Klu1d]

In your photo, at least visually, everything looks the same as in mine. This example, which is shown in your screenshot, works fine on my system.

I will add that I have a window manager that is included when installing Ubuntu - mutter. The window interface is Wayland.

I will also supplement my question: I realized that when adding the "content" parameter to an object of the Tab class, it throws the presented error. At the same time, if I transfer the code from the Sec class to the 'main' function, then it will work calmly

[FeodorFitsner]

Indeed, I can reproduce the issue with tabs on Ubuntu:

[FeodorFitsner]

OK, found the issue! User control itself must be expanded (self.expand = True):

from flet import (
    Container,
    UserControl,
    Tabs, Tab,
    Page,
    app
)

class Sec(UserControl):
    def build(self):

        self.expand = True
        self.tabs = Tabs(
            animation_duration=300,
            selected_index=0,
            tabs=[
                Tab(text="STORAGE", content=Container(bgcolor='red')),
                Tab(text="FILE", content=Container(bgcolor='blue')),
            ],
            expand=1,
        )
        
        return self.tabs
    

def main(page: Page):

    tol = Sec()
    page.add(tol)

app(target=main)

I have to admit the error is misleading.