Daybreak/Daybreak.Core/Views/Components/FocusView/BrowserComponent.razor

<div class="browser-container @(this.IsMaximized ? "maximized" : string.Empty)">
    <button class="browser-toggle-button"
            title="@(this.IsMaximized ? "Restore" : "Expand to fullscreen")"
            @onclick="this.ToggleMaximized"
            @onclick:stopPropagation="true">
        <FluentIcon Value="@(this.IsMaximized ?
            (Microsoft.FluentUI.AspNetCore.Components.Icon)new Microsoft.FluentUI.AspNetCore.Components.Icons.Regular.Size16.ArrowMinimize() :
            new Microsoft.FluentUI.AspNetCore.Components.Icons.Regular.Size16.ArrowMaximize())" />
    </button>
    <iframe sandbox="allow-scripts allow-same-origin allow-forms"
            class="browser-frame"
            src="@this.Source" />
</div>

@code {
    [Parameter]
    public string? Source { get; init; }
    [Parameter]
    public Action? OnMaximized { get; init; }
    [Parameter]
    public Action? OnRestore { get; init; }

    private bool IsMaximized { get; set; }

    private void ToggleMaximized()
    {
        this.IsMaximized = !this.IsMaximized;
        if (this.IsMaximized)
        {
            this.OnMaximized?.Invoke();
        }
        else
        {
            this.OnRestore?.Invoke();
        }
    }
}