From 276efed48ae0dbaefd62c200acffd57a273add6b Mon Sep 17 00:00:00 2001
From: GabrielDuf <gabrielduf@hotmail.com>
Date: Thu, 20 Aug 2026 13:47:13 -0400
Subject: [PATCH 1/2] Stop the pressed shrink from cancelling caption-button
 clicks

Fluent's Button style applies RenderTransform scale(0.98) on :pressed with
a 75 ms TransformOperationsTransition, and Button.OnPointerReleased only
raises Click when the release position still hit-tests onto the button. On
a 46x44 caption button that shrink pulls every edge ~0.45 DIP inward while
the button is held, so a press on the outermost pixel row or column lands
on the button, the geometry moves out from under the stationary pointer,
and the release finds TitleBarDragArea instead: the button keeps its
pressed fill and nothing happens.

Measured on a maximized window, minimize on the top row: the button's clip
goes from (1590, 0, 46, 44) at press to (1590.36, 0.34, 45.28, 43.31) at
release, with IsPointerOver false. Injected clicks on that row went 0/8
before this change and 8/8 after.

Native caption buttons don't shrink on press, so opt ours out of the
transform and keep the background-only state change. The outcome depended
on how far the 75 ms transition had run at release, which is why it
reproduced on one monitor and not another.

Fixes #5269

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
---
 src/UniGetUI.Avalonia/Views/MainWindow.axaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/UniGetUI.Avalonia/Views/MainWindow.axaml b/src/UniGetUI.Avalonia/Views/MainWindow.axaml
index dbd6127101..383efed2b9 100644
--- a/src/UniGetUI.Avalonia/Views/MainWindow.axaml
+++ b/src/UniGetUI.Avalonia/Views/MainWindow.axaml
@@ -68,6 +68,9 @@
             <Setter Property="Background" Value="{DynamicResource SubtleFillColorSecondaryBrush}"/>
             <Setter Property="CornerRadius" Value="0"/>
         </Style>
+        <Style Selector="Button.caption:pressed">
+            <Setter Property="RenderTransform" Value="none"/>
+        </Style>
         <Style Selector="Button.caption:pressed /template/ ContentPresenter">
             <Setter Property="Background" Value="{DynamicResource SubtleFillColorTertiaryBrush}"/>
             <Setter Property="CornerRadius" Value="0"/>

From 30ed06419e3c7699d25b6aa0858db5ba224fd5f8 Mon Sep 17 00:00:00 2001
From: GabrielDuf <gabrielduf@hotmail.com>
Date: Thu, 20 Aug 2026 13:47:26 -0400
Subject: [PATCH 2/2] Give the caption buttons the resize-border pixels they
 cover

Avalonia's HitTestNCA hands the WS_THICKFRAME border to HTTOP / HTRIGHT /
HTTOPRIGHT and CustomCaptionProc never lets the visual tree override those
results, so wherever that border overlaps our custom caption buttons the
pixels are non-client: clicks there start a resize instead of pressing the
button, and no pointer-leave is synthesised, so the button keeps its hover
fill and looks live. The border is skipped only while the window is
natively maximized (Windows then places the frame outside the work area),
so it bites floating and snapped windows.

Measured on a floating window at 200%: the top 12 px reported TOP and the
rightmost 13 px of the close button reported RIGHT, swallowing every click,
while 20 px in worked.

Claim the whole WindowButtons rect as HTCLIENT from the existing
WM_NCHITTEST hook, which runs before Avalonia's WndProc, so the buttons own
their own pixels in every window state. Resizing stays available along the
rest of the top edge and down the right edge below the strip, and the
maximize button keeps its HTMAXBUTTON claim so Snap Layouts still attach.
Injected clicks on a floating window close 3/3 at 1, 6 and 13 px from the
right edge, versus 0/3 at 1 px before.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
---
 .../Views/MainWindow.axaml.cs                 | 33 +++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/src/UniGetUI.Avalonia/Views/MainWindow.axaml.cs b/src/UniGetUI.Avalonia/Views/MainWindow.axaml.cs
index 05b2b466b6..108b2e3ef8 100644
--- a/src/UniGetUI.Avalonia/Views/MainWindow.axaml.cs
+++ b/src/UniGetUI.Avalonia/Views/MainWindow.axaml.cs
@@ -97,6 +97,7 @@ public partial class MainWindow : Window
     private const uint WM_DWMCOLORIZATIONCOLORCHANGED = 0x0320;
     private const nint SC_MAXIMIZE = 0xF030;
     private const nint SC_RESTORE = 0xF120;
+    private const int HTCLIENT = 1;
     private const int HTMAXBUTTON = 9;
     private const uint TME_LEAVE = 0x0002;
     private const uint TME_NONCLIENT = 0x0010;
@@ -978,8 +979,7 @@ private bool HitTestMaximizeButton(nint lParam)
             return false;
         try
         {
-            int x = unchecked((short)(lParam.ToInt64() & 0xFFFF));
-            int y = unchecked((short)((lParam.ToInt64() >> 16) & 0xFFFF));
+            var (x, y) = ScreenPointFromLParam(lParam);
             PixelPoint topLeft = MaximizeButton.PointToScreen(new Point(0, 0));
             PixelPoint bottomRight = MaximizeButton.PointToScreen(
                 new Point(MaximizeButton.Bounds.Width, MaximizeButton.Bounds.Height));
@@ -991,6 +991,30 @@ private bool HitTestMaximizeButton(nint lParam)
         }
     }
 
+    private bool HitTestCaptionButtons(nint lParam)
+    {
+        if (!WindowButtons.IsVisible)
+            return false;
+        try
+        {
+            var (x, y) = ScreenPointFromLParam(lParam);
+            PixelPoint topLeft = WindowButtons.PointToScreen(new Point(0, 0));
+            PixelPoint bottomRight = WindowButtons.PointToScreen(
+                new Point(WindowButtons.Bounds.Width, WindowButtons.Bounds.Height));
+            return x >= topLeft.X && x < bottomRight.X && y >= topLeft.Y && y < bottomRight.Y;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private static (int X, int Y) ScreenPointFromLParam(nint lParam)
+    {
+        long packed = lParam.ToInt64();
+        return (unchecked((short)(packed & 0xFFFF)), unchecked((short)((packed >> 16) & 0xFFFF)));
+    }
+
     // Emulates the button's pointer-over/pressed fill (lost once input is non-client) using the
     // same Fluent brushes the neighbouring min/close buttons use, so the row stays consistent.
     private void SetMaximizeButtonVisual(bool hover, bool pressed)
@@ -1130,6 +1154,11 @@ private static nint OnWindowsWndProc(nint hWnd, uint msg, nint wParam, nint lPar
                         handled = true;
                         return HTMAXBUTTON;
                     }
+                    if (self.HitTestCaptionButtons(lParam))
+                    {
+                        handled = true;
+                        return HTCLIENT;
+                    }
                     break;
 
                 case WM_NCMOUSEMOVE: