Force double SetWindowPos for BarWindow (#886)

It seems this is necessary for windows in monitors with 100% scaling. This will need further investigation in #887 for the difference in behavior between C# and what's fetched from the XAML.

docs/docs/customize/styling.md

@@ -64,7 +64,7 @@ The `bar:height` key is a special key that is used to communicate to Whim the de
 Notes:
 
 - The corresponding style must not contain any property other than `Height`.
-- This setting is overwritten if `Height` is explicitly set in <xref:Whim.Bar.BarConfig>.
+- This setting is overwritten if `Height` is explicitly set in <xref:Whim.Bar.BarConfig> - this may be required in some monitor configurations - tracked in [#887](https://github.com/dalyIsaac/Whim/issues/887)
 - The actual height of the bar may differ from the specified one due to overflowing elements.
 
 > [!NOTE]

src/Whim.Bar/BarPlugin.cs

@@ -79,7 +79,7 @@ private void ShowAll()
 		foreach (BarWindow barWindow in _monitorBarMap.Values)
 		{
 			barWindow.UpdateRect();
-			deferPosHandle.DeferWindowPos(barWindow.WindowState);
+			deferPosHandle.DeferWindowPos(barWindow.WindowState, forceTwoPasses: true);
 			_context.NativeManager.SetWindowCorners(
 				barWindow.WindowState.Window.Handle,
 				DWM_WINDOW_CORNER_PREFERENCE.DWMWCP_DONOTROUND

src/Whim.Tests/Native/DeferWindowPosHandleTests.cs

@@ -170,6 +170,43 @@ WindowPosState windowPosState2
 		AssertSetWindowPos(internalCtx, windowPosState2, expectedCallCount: numPasses);
 	}
 
+	[Theory, AutoSubstituteData<DeferWindowPosHandleCustomization>]
+	internal void Dispose_ForceTwoPasses(
+		IContext ctx,
+		IInternalContext internalCtx,
+		WindowPosState windowPosState1,
+		WindowPosState windowPosState2
+	)
+	{
+		// Given multiple windows, and a monitor which has a scale factor == 100
+		int monitorScaleFactor = 100;
+		int numPasses = 2;
+
+		using DeferWindowPosHandle handle = new(ctx, internalCtx);
+		internalCtx.DeferWindowPosManager.CanDoLayout().Returns(true);
+
+		IMonitor monitor1 = Substitute.For<IMonitor>();
+		monitor1.ScaleFactor.Returns(100);
+		IMonitor monitor2 = Substitute.For<IMonitor>();
+		monitor2.ScaleFactor.Returns(monitorScaleFactor);
+
+		ctx.MonitorManager.GetEnumerator().Returns((_) => new List<IMonitor>() { monitor1, monitor2 }.GetEnumerator());
+
+		// When disposing
+		handle.DeferWindowPos(windowPosState1.WindowState, windowPosState1.HwndInsertAfter, windowPosState1.Flags);
+		handle.DeferWindowPos(
+			windowPosState2.WindowState,
+			windowPosState2.HwndInsertAfter,
+			windowPosState2.Flags,
+			forceTwoPasses: true
+		);
+		handle.Dispose();
+
+		// Then the windows are laid out twice
+		AssertSetWindowPos(internalCtx, windowPosState1, expectedCallCount: numPasses);
+		AssertSetWindowPos(internalCtx, windowPosState2, expectedCallCount: numPasses);
+	}
+
 	[Theory, AutoSubstituteData<DeferWindowPosHandleCustomization>]
 	internal void Dispose_NoWindowOffset(IContext ctx, IInternalContext internalCtx, WindowPosState windowPosState)
 	{

src/Whim/Native/DeferWindowPosHandle.cs

@@ -23,6 +23,8 @@ public sealed class DeferWindowPosHandle : IDisposable
 	private readonly List<WindowPosState> _windowStates = new();
 	private readonly List<WindowPosState> _minimizedWindowStates = new();
 
+	private bool forceTwoPasses;
+
 	/// <summary>
 	/// The default flags to use when setting the window position.
 	/// </summary>
@@ -80,13 +82,25 @@ IEnumerable<WindowPosState> windowStates
 	/// The flags to use when setting the window position. This overrides the default flags Whim sets,
 	/// except when the window is maximized or minimized.
 	/// </param>
+	/// <param name="forceTwoPasses">
+	/// Window scaling can be finicky. Whim will set a window's position twice for windows in monitors
+	/// with non-100% scaling. Regardless of this, some windows need this even for windows with
+	/// 100% scaling.
+	/// </param>
 	public void DeferWindowPos(
 		IWindowState windowState,
 		HWND? hwndInsertAfter = null,
-		SET_WINDOW_POS_FLAGS? flags = null
+		SET_WINDOW_POS_FLAGS? flags = null,
+		bool forceTwoPasses = false
 	)
 	{
 		Logger.Debug($"Adding window {windowState.Window} after {hwndInsertAfter} with flags {flags}");
+
+		if (forceTwoPasses)
+		{
+			this.forceTwoPasses = true;
+		}
+
 		// We use HWND_BOTTOM, as modifying the Z-order of a window
 		// may cause EVENT_SYSTEM_FOREGROUND to be set, which in turn
 		// causes the relevant window to be focused, when the user hasn't
@@ -136,7 +150,7 @@ public void Dispose()
 		int numPasses = 1;
 		foreach (IMonitor monitor in _context.MonitorManager)
 		{
-			if (monitor.ScaleFactor != 100)
+			if (monitor.ScaleFactor != 100 || forceTwoPasses)
 			{
 				numPasses = 2;
 				break;