Cleaned up implementation of ShowTaskbarIcon

Created property in Window to enable/disable the taskbar icon

src/Avalonia.Controls/Platform/IWindowImpl.cs

@@ -31,7 +31,7 @@ namespace Avalonia.Platform
         IDisposable ShowDialog();
 
         /// <summary>
-        /// Enables of disables system window decorations (title bar, buttons, etc)
+        /// Enables or disables system window decorations (title bar, buttons, etc)
         /// </summary>
         void SetSystemDecorations(bool enabled);
 
@@ -40,8 +40,9 @@ namespace Avalonia.Platform
         /// </summary>
         void SetIcon(IWindowIconImpl icon);
 
-
+        /// <summary>
-
+        /// Enables or disables the taskbar icon
+        /// </summary>
         void ShowTaskbarIcon(bool value);
     }
 }

src/Avalonia.Controls/Window.cs

@@ -61,11 +61,17 @@ namespace Avalonia.Controls
             AvaloniaProperty.Register<Window, SizeToContent>(nameof(SizeToContent));
 
         /// <summary>
-        /// Enables of disables system window decorations (title bar, buttons, etc)
+        /// Enables or disables system window decorations (title bar, buttons, etc)
         /// </summary>
         public static readonly StyledProperty<bool> HasSystemDecorationsProperty =
             AvaloniaProperty.Register<Window, bool>(nameof(HasSystemDecorations), true);
-
+        
+        /// <summary>
+        /// Enables or disables the taskbar icon
+        /// </summary>
+        public static readonly StyledProperty<bool> HasTaskbarIconProperty =
+            AvaloniaProperty.Register<Window, bool>(nameof(HasTaskbarIcon), true);
+        
         /// <summary>
         /// Defines the <see cref="Title"/> property.
         /// </summary>
@@ -92,6 +98,8 @@ namespace Avalonia.Controls
             HasSystemDecorationsProperty.Changed.AddClassHandler<Window>(
                 (s, e) => s.PlatformImpl?.SetSystemDecorations((bool) e.NewValue));
 
+            HasTaskbarIconProperty.Changed.AddClassHandler<Window>((w, e) => w.PlatformImpl?.ShowTaskbarIcon((bool)e.NewValue));
+
             IconProperty.Changed.AddClassHandler<Window>((s, e) => s.PlatformImpl?.SetIcon(((WindowIcon)e.NewValue).PlatformImpl));
         }
 
@@ -152,7 +160,7 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Enables of disables system window decorations (title bar, buttons, etc)
+        /// Enables or disables system window decorations (title bar, buttons, etc)
         /// </summary>
         /// 
         public bool HasSystemDecorations
@@ -160,6 +168,16 @@ namespace Avalonia.Controls
             get { return GetValue(HasSystemDecorationsProperty); }
             set { SetValue(HasSystemDecorationsProperty, value); }
         }
+        
+        /// <summary>
+        /// Enables or disables the taskbar icon
+        /// </summary>
+        /// 
+        public bool HasTaskbarIcon
+        {
+            get { return GetValue(HasTaskbarIconProperty); }
+            set { SetValue(HasTaskbarIconProperty, value); }
+        }
 
         /// <summary>
         /// Gets or sets the minimized/maximized state of the window.

src/Gtk/Avalonia.Gtk/WindowImpl.cs

@@ -6,11 +6,12 @@ using Gdk;
 namespace Avalonia.Gtk
 {
     using Gtk = global::Gtk;
+
     public class WindowImpl : TopLevelImpl, IWindowImpl
     {
         private Gtk.Window _window;
-        private Gtk.Window Window => _window ?? (_window = (Gtk.Window) Widget);
+        private Gtk.Window Window => _window ?? (_window = (Gtk.Window)Widget);
-        
+
         public WindowImpl(Gtk.WindowType type) : base(new PlatformHandleAwareWindow(type))
         {
             Init();
@@ -29,8 +30,10 @@ namespace Avalonia.Gtk
             _lastClientSize = ClientSize;
             _lastPosition = Position;
         }
+
         private Size _lastClientSize;
         private Point _lastPosition;
+
         void OnConfigureEvent(object o, Gtk.ConfigureEventArgs args)
         {
             var evnt = args.Event;
@@ -44,7 +47,7 @@ namespace Avalonia.Gtk
             }
 
             var newPosition = new Point(evnt.X, evnt.Y);
-            
+
             if (newPosition != _lastPosition)
             {
                 PositionChanged(newPosition);
@@ -107,10 +110,7 @@ namespace Avalonia.Gtk
                 Window.GetPosition(out x, out y);
                 return new Point(x, y);
             }
-            set
+            set { Window.Move((int)value.X, (int)value.Y); }
-            {
-                Window.Move((int)value.X, (int)value.Y);
-            }
         }
 
         public IDisposable ShowDialog()
@@ -128,9 +128,6 @@ namespace Avalonia.Gtk
             Window.Icon = ((IconImpl)icon).Pixbuf;
         }
 
-        public void ShowTaskbarIcon(bool value)
+        public void ShowTaskbarIcon(bool value) => Window.SkipTaskbarHint = !value;
-        {
-            Window.SkipTaskbarHint = !value;
-        }
     }
-}
+}

src/Gtk/Avalonia.Gtk3/WindowImpl.cs

@@ -60,10 +60,8 @@ namespace Avalonia.Gtk3
             //Why do we even have that?
         }
 
-        public void ShowTaskbarIcon(bool value)
+        public void ShowTaskbarIcon(bool value) => Native.GtkWindowSetSkipTaskbarHint(GtkWidget, !value);
-        {
+        
-            Native.GtkWindowSetSkipTaskbarHint(GtkWidget, !value);
-        }
 
         class EmptyDisposable : IDisposable
         {

src/Windows/Avalonia.Win32/WindowImpl.cs

@@ -763,6 +763,7 @@ namespace Avalonia.Win32
             else
                 style &= ~(UnmanagedMethods.WindowStyles.WS_EX_APPWINDOW);
 
+            //Toggle to make the styles stick
             UnmanagedMethods.ShowWindow(_hwnd, ShowWindowCommand.Hide);
             UnmanagedMethods.SetWindowLong(_hwnd, -20, (uint)style);
             UnmanagedMethods.ShowWindow(_hwnd, ShowWindowCommand.Show);