After first backdrop toggle: back layer revealed on every front layer click regardless of location

[WieFel]

Describe the bug
In a very simple setting, after having toggled backdrop for the first time (to reveal back layer), the front layer becomes non-responsive and toggles backdrop on every front layer click.

To Reproduce
Steps to reproduce the behavior:
Use this code

    MaterialApp(
      title: 'Backdrop Demo',
      home: BackdropScaffold(
        appBar: BackdropAppBar(
          title: Text("Backdrop Example"),
          actions: <Widget>[
            BackdropToggleButton(
              icon: AnimatedIcons.list_view,
            )
          ],
        ),
        backLayer: Center(
          child: Text("Back Layer"),
        ),
        subHeader: BackdropSubHeader(
          title: Text("Sub Header"),
        ),
        frontLayer: Center(
          child: MaterialButton(
            child: Text("Click"),
            onPressed: () => print("Clicked!"),
          ),
        ),
      ),
    );

1. Click anywhere on front layer (nothing should happen)
2. Toggle backdrop to reveal back layer
3. Toggle backdrop to conceal back layer
4. Click anywhere on front layer (back layer is revealed)
5. Toggle backdrop again to conceal back layer
6. Try to click on front layer button (button cannot be clicked, and backdrop is toggled instead)

Expected behavior
Backdrop should not be toggled from front layer if it is revealed.

Screenshots
Should be clear enough as is.

[daadu]

I am not able to reproduce the bug

[WieFel]

Ok, let me check on other devices...
@daadu are you running flutter stable channel or something else?

[WieFel]

The problem is related with the beta channel. On stable channel, I cannot reproduce it either.
I am experiencing the problem while developing the demo app, which needs the beta channel for flutter web support...

[daadu]

beta will probably land on stable channel some day. we need to fix this then.

[WieFel]

Yes, I'll have a look at it.