Flyout Wont work on Wasm / SKIA

[iurycarlos]

Current behavior

Flyout is failing to appear right after 5.1 update.

Expected behavior

Flyout should appear as expected.

How to reproduce it (as minimally and precisely as possible)

1. Update UNO-Check
2. Run uno-check to make sure to have the latest template
3. Create a sample app and add a button with a flyout. In my case I just added a TextBlock inside the flyout.

      <Button Content="Bottom">
        <Button.Flyout>
          <Flyout Placement="Bottom" >
            <TextBlock Text="Testing the Flyout" Foreground="Red" />
          </Flyout>
        </Button.Flyout>
      </Button>
      <Button Content="Top">
        <Button.Flyout>
          <Flyout Placement="Top" >
            <TextBlock Text="Testing the Flyout" Foreground="Red" />
          </Flyout>
        </Button.Flyout>
      </Button>
      <Button Content="None">
        <Button.Flyout>
          <Flyout>
            <TextBlock Text="Testing the Flyout" Foreground="Red" />
          </Flyout>
        </Button.Flyout>
      </Button>

   SNIPPET IN PLAYGROUND
4. Run it on Skia (to have console logs easily)
5. Right after clicking the button you will got an error like:

Important and curiously:

If you resize the window, you will get the following message at next button click:

warn: Microsoft.UI.Xaml.Controls.Primitives.PopupPanel[0]
anchorSize is 0

And now, if you click the button again, the flyout will appear

Workaround

No response

Works on UWP/WinUI

None

Environment

No response

NuGet package version(s)

No response

Affected platforms

No response

IDE

No response

IDE version

No response

Relevant plugins

No response

Anything else we need to know?

No response

[jeromelaban]

Related to #15240. A workaround is to remove the NaN that you likely have in your styles.

[iurycarlos]

In case it helps, the version which started the issue is :

5.1.0-dev.1459

[carldebilly]

Related to #15240. A workaround is to remove the NaN that you likely have in your styles.

@jeromelaban, it's doing that in a brand new app, so which style should be overriden to fix it?

[Youssef1313]

Likely fixed in unoplatform/uno.toolkit.ui#1010 and unoplatform/Uno.Themes#1338

[Youssef1313]

Fix is backported.

unoplatform/Uno.Themes#1342