Prevent window from stealing focus

Hyperbar.Windows.Interop/ExtendedWindowStyle.cs

@@ -0,0 +1,33 @@
+namespace Hyperbar.Windows.Interop;
+
+[Flags]
+public enum ExtendedWindowStyle
+{
+    AcceptFiles = 0x10,
+    AppWindow = 0x40000,
+    ClientEdge = 0x200,
+    Composited = 0x2000000,
+    ContextHelp = 0x400,
+    ControlParent = 0x10000,
+    DlgModalFrame = 1,
+    Layered = 0x80000,
+    LayoutRtl = 0x400000,
+    Left = 0,
+    LeftScrollBar = 0x4000,
+    LtrReading = 0,
+    MdiChild = 0x40,
+    NoActivate = 0x8000000,
+    NoInheritLayout = 0x100000,
+    NoParentNotify = 4,
+    NoRedirectionBitmap = 0x200000,
+    OverlappedWindow = 0x300,
+    PaletteWindow = 0x188,
+    Right = 0x1000,
+    RightScrollBar = 0,
+    RtlReading = 0x2000,
+    StaticEdge = 0x20000,
+    ToolWindow = 0x80,
+    TopMost = 8,
+    Transparent = 0x20,
+    WindowEdge = 0x100
+}

Hyperbar.Windows.Interop/HwndExtensions.cs

@@ -15,8 +15,23 @@ public static class HwndExtensions
         WS_EX_LAYERED = 0x80000
     }
 
+    public static void SetExtendedWindowStyle(this IntPtr hwnd, ExtendedWindowStyle newStyle)
+    {
+        int windowLong = PInvoke.GetWindowLong(new(hwnd), WINDOW_LONG_PTR_INDEX.GWL_EXSTYLE);
+        if (PInvoke.SetWindowLong(new(hwnd), WINDOW_LONG_PTR_INDEX.GWL_EXSTYLE, (int)newStyle) != windowLong)
+        {
+            Marshal.ThrowExceptionForHR(Marshal.GetLastWin32Error());
+        }
+
+        PInvoke.SetWindowPos(new(hwnd), new HWND(0), 0, 0, 0, 0, SET_WINDOW_POS_FLAGS.SWP_DRAWFRAME |
+            SET_WINDOW_POS_FLAGS.SWP_NOMOVE |
+            SET_WINDOW_POS_FLAGS.SWP_NOOWNERZORDER |
+            SET_WINDOW_POS_FLAGS.SWP_NOSIZE |
+            SET_WINDOW_POS_FLAGS.SWP_NOZORDER);
+    }
+
     public static void SetWindowOpacity(this IntPtr hWnd,
-        byte value)
+            byte value)
     {
         HWND hWND = new(hWnd);
         WindowStyles windowLong = (WindowStyles)PInvoke.GetWindowLong(hWND, WINDOW_LONG_PTR_INDEX.GWL_EXSTYLE);
@@ -30,7 +45,6 @@ public static class HwndExtensions
             Marshal.ThrowExceptionForHR(Marshal.GetLastWin32Error());
         }
     }
-
     public static void SetWindowStyle(this IntPtr hwnd,
         WindowStyle newStyle)
     {

Hyperbar.Windows.Interop/WindowStyle.cs

@@ -30,4 +30,4 @@ public enum WindowStyle
     TiledWindow = 0xCF0000,
     Visible = 0x10000000,
     VScroll = 0x200000
-}
+}