SplitView ":open"/":closed" pseudoclasses aren't set on control initialization

[OccVeneficus]

Describe the bug

SplitView control after it initialized does not have :open or :closed pseudoclass set. Regardless of the value in the IsPaneOpen property.

To Reproduce

Create Window with a SplitView control, set IsPaneOpen to any value (e.g, by binding to ViewModel)
Run the application in Debug, open Debug tools
In Logical Tree, find SplitView. The SplitView doesn't have :open / :closed pseudoclass set regardless of the value in the IsPaneOpen property.

Pseudoclass is set only after first change of IsPaneOpen property

Expected behavior

SplitView control after initialization should have :open / :closed pseudoclass set depending of the value in the IsPaneOpen property

Avalonia version

11.1.0

OS

Windows

Additional context

After looking into SplitView.cs source code, the problem appears to be that the logic for changing pseudoclass based on IsPaneOpen value is present only in OnPropertyChanged method. Adding same logic to constructor should fix the issue

[timunie]

@OccVeneficus if you have an idea how to solve it, a PR is welcome.

[OccVeneficus]

@OccVeneficus if you have an idea how to solve it, a PR is welcome.

Created PR with fix. While working on it discovered that issue reproduces only if before added on view tree IsPaneOpen property is set to false, in that case :closed pseudoclass won't be added after control first rendered.