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Is the linked issue really resolved? CaptionButtons are still visible.

We're just supporting what the various platforms are exposing here.

On Windows, if Maximize and Minimize are both disabled, the system automatically hides both buttons.
On macOS, the traffic lights are kept, but disabled (see the "about this mac" system window).
On Linux, it totally depends on the window manager and its configuration.

To do more, it's always possible for users to use a custom chrome.

You can test this PR using the following package version. 11.3.999-cibuild0054781-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

I think hint in the name makes more sense and follows the existing pattern of things that may or may not work.

Couple thoughts:

1. Have you considered a higher level of abstraction like with WPF? WPF has the WindowStyle enum to control this. It might help here in some cases:
   • Do we really need to support maximize but not minimize? Usually a window is resisable or it is not.
   • A WindowStyle could have a value such as NotResizeable. On windows that would remove the minimize/maximize buttons completely but on macOS would just disable them. So this generic naming doesn't imply how the actual buttons are shown which allows the platforms to handle it natively.
2. For some reason I'm not a fan of "Hint" in this context. But I also agree it is more of a "Hint" on the platforms such as Linux that don't support all cases. I guess my justification is the main platforms support these properties just fine so its a shame to use less-than-ideal naming just because of limitations of a minor platform.

Public API for review:

namespace Avalonia.Controls
{
    public class Window : WindowBase, IFocusScope, ILayoutRoot
    {
+        public static readonly StyledProperty<bool> CanMinimizeProperty;
+        public static readonly StyledProperty<bool> CanMaximizeProperty;
+        public bool CanMinimize { get; set; }
+        public bool CanMaximize { get; set; }
    }
}

namespace Avalonia.Platform
{
    [Unstable]
    public interface IWindowImpl : IWindowBaseImpl
    {
+        void SetCanMinimize(bool value);
+        void SetCanMaximize(bool value);
    }
}

During the API review meeting, it was noted that all 3 desktop platforms each provide some minimize and maximize flags directly. This new API maps to those perfectly and we decided not to add a higher level concept, that might require users to fiddle with several properties to set a single flag.

We focused mostly on the fact that CanMinimize/CanMaximize aren't technically correct. The actual use case is to disable/hide the title bar buttons, but the OS or a third party application might still be able to minimize/maximize the window, making the "Can" part technically wrong.

However, after some debate on the naming, CanMinimize/Maximize is still the winner, as it's simple enough and probably what the user would look for. Hint didn't get much traction.

The API is accepted.

Note: this PR still needs integration tests.

Integration tests have been added.

You can test this PR using the following package version. 12.0.999-cibuild0058006-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

You can test this PR using the following package version. 12.0.999-cibuild0058014-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]