Native window decorations: show Windows 11 snap layouts menu when hovering the mouse over the maximize button (issues #397 and #407)

CHANGELOG.md

@@ -12,6 +12,8 @@ FlatLaf Change Log
   - Style classes allow defining style rules at a single place (in UI defaults)
     and use them in any component. (PR #388)\
     E.g.: `mySlider.putClientProperty( "FlatLaf.styleClass", "myclass" );`
+- Native window decorations: Show Windows 11 snap layouts menu when hovering the
+  mouse over the maximize button. (issues #397 and #407)
 - TextField, FormattedTextField and PasswordField: Support leading and trailing
   icons (set client property `JTextField.leadingIcon` or
   `JTextField.trailingIcon` to an `Icon`). (PR #378; issue #368)

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeWindowBorder.java

@@ -235,7 +235,7 @@ public class FlatNativeWindowBorder
 	}
 
 	static void setTitleBarHeightAndHitTestSpots( Window window, int titleBarHeight,
-		List<Rectangle> hitTestSpots, Rectangle appIconBounds )
+		List<Rectangle> hitTestSpots, Rectangle appIconBounds, Rectangle maximizeButtonBounds )
 	{
 		if( canUseJBRCustomDecorations ) {
 			JBRCustomDecorations.setTitleBarHeightAndHitTestSpots( window, titleBarHeight, hitTestSpots );
@@ -245,9 +245,7 @@ public class FlatNativeWindowBorder
 		if( !isSupported() )
 			return;
 
-		nativeProvider.setTitleBarHeight( window, titleBarHeight );
-		nativeProvider.setTitleBarHitTestSpots( window, hitTestSpots );
-		nativeProvider.setTitleBarAppIconBounds( window, appIconBounds );
+		nativeProvider.updateTitleBarInfo( window, titleBarHeight, hitTestSpots, appIconBounds, maximizeButtonBounds );
 	}
 
 	static boolean showWindow( Window window, int cmd ) {
@@ -292,9 +290,8 @@ public class FlatNativeWindowBorder
 	{
 		boolean hasCustomDecoration( Window window );
 		void setHasCustomDecoration( Window window, boolean hasCustomDecoration );
-		void setTitleBarHeight( Window window, int titleBarHeight );
-		void setTitleBarHitTestSpots( Window window, List<Rectangle> hitTestSpots );
-		void setTitleBarAppIconBounds( Window window, Rectangle appIconBounds );
+		void updateTitleBarInfo( Window window, int titleBarHeight, List<Rectangle> hitTestSpots,
+			Rectangle appIconBounds, Rectangle maximizeButtonBounds );
 
 		// commands for showWindow(); values must match Win32 API
 		// https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-showwindow

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTitlePane.java

@@ -527,11 +527,17 @@ public class FlatTitlePane
 				g.drawRect( r.x - offset.x, r.y - offset.y, r.width - 1, r.height - 1 );
 		}
 		if( debugAppIconBounds != null ) {
-			g.setColor( Color.blue);
+			g.setColor( Color.blue );
 			Point offset = SwingUtilities.convertPoint( this, 0, 0, window );
 			Rectangle r = debugAppIconBounds;
 			g.drawRect( r.x - offset.x, r.y - offset.y, r.width - 1, r.height - 1 );
 		}
+		if( debugMaximizeButtonBounds != null ) {
+			g.setColor( Color.blue );
+			Point offset = SwingUtilities.convertPoint( this, 0, 0, window );
+			Rectangle r = debugMaximizeButtonBounds;
+			g.drawRect( r.x - offset.x, r.y - offset.y, r.width - 1, r.height - 1 );
+		}
 	}
 debug*/
 
@@ -722,6 +728,7 @@ debug*/
 
 		List<Rectangle> hitTestSpots = new ArrayList<>();
 		Rectangle appIconBounds = null;
+
 		if( iconLabel.isVisible() ) {
 			// compute real icon size (without insets; 1px wider for easier hitting)
 			Point location = SwingUtilities.convertPoint( iconLabel, 0, 0, window );
@@ -753,6 +760,13 @@ debug*/
 				appIconBounds = iconBounds;
 		}
 
+		JButton maxButton = maximizeButton.isVisible()
+			? maximizeButton
+			: (restoreButton.isVisible() ? restoreButton : null);
+		Rectangle maximizeButtonBounds = (maxButton != null)
+			? SwingUtilities.convertRectangle( maxButton.getParent(), maxButton.getBounds(), window )
+			: null;
+
 		Rectangle r = getNativeHitTestSpot( buttonPanel );
 		if( r != null )
 			hitTestSpots.add( r );
@@ -787,12 +801,14 @@ debug*/
 			}
 		}
 
-		FlatNativeWindowBorder.setTitleBarHeightAndHitTestSpots( window, titleBarHeight, hitTestSpots, appIconBounds );
+		FlatNativeWindowBorder.setTitleBarHeightAndHitTestSpots( window, titleBarHeight,
+			hitTestSpots, appIconBounds, maximizeButtonBounds );
 
 /*debug
 		debugTitleBarHeight = titleBarHeight;
 		debugHitTestSpots = hitTestSpots;
 		debugAppIconBounds = appIconBounds;
+		debugMaximizeButtonBounds = maximizeButtonBounds;
 		repaint();
 debug*/
 	}
@@ -815,6 +831,7 @@ debug*/
 	private int debugTitleBarHeight;
 	private List<Rectangle> debugHitTestSpots;
 	private Rectangle debugAppIconBounds;
+	private Rectangle debugMaximizeButtonBounds;
 debug*/
 
 	//---- class FlatTitlePaneBorder ------------------------------------------

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowsNativeWindowBorder.java

@@ -54,6 +54,10 @@ import com.formdev.flatlaf.util.SystemInfo;
 //     https://github.com/oberth/custom-chrome
 //     https://github.com/rossy/borderless-window
 //
+//   Windows 11
+//     https://docs.microsoft.com/en-us/windows/apps/desktop/modernize/apply-snap-layout-menu
+//     https://github.com/dotnet/wpf/issues/4825#issuecomment-930442736
+//
 
 /**
  * Native window border support for Windows 10 when using custom decorations.
@@ -177,30 +181,17 @@ class FlatWindowsNativeWindowBorder
 	}
 
 	@Override
-	public void setTitleBarHeight( Window window, int titleBarHeight ) {
+	public void updateTitleBarInfo( Window window, int titleBarHeight, List<Rectangle> hitTestSpots,
+		Rectangle appIconBounds, Rectangle maximizeButtonBounds )
+	{
 		WndProc wndProc = windowsMap.get( window );
 		if( wndProc == null )
 			return;
 
 		wndProc.titleBarHeight = titleBarHeight;
-	}
-
-	@Override
-	public void setTitleBarHitTestSpots( Window window, List<Rectangle> hitTestSpots ) {
-		WndProc wndProc = windowsMap.get( window );
-		if( wndProc == null )
-			return;
-
 		wndProc.hitTestSpots = hitTestSpots.toArray( new Rectangle[hitTestSpots.size()] );
-	}
-
-	@Override
-	public void setTitleBarAppIconBounds( Window window, Rectangle appIconBounds ) {
-		WndProc wndProc = windowsMap.get( window );
-		if( wndProc == null )
-			return;
-
 		wndProc.appIconBounds = (appIconBounds != null) ? new Rectangle( appIconBounds ) : null;
+		wndProc.maximizeButtonBounds = (maximizeButtonBounds != null) ? new Rectangle( maximizeButtonBounds ) : null;
 	}
 
 	@Override
@@ -303,14 +294,17 @@ class FlatWindowsNativeWindowBorder
 			HTCLIENT = 1,
 			HTCAPTION = 2,
 			HTSYSMENU = 3,
+			HTMAXBUTTON = 9,
 			HTTOP = 12;
 
 		private Window window;
 		private final long hwnd;
 
+		// Swing coordinates/values may be scaled on a HiDPI screen
 		private int titleBarHeight;
 		private Rectangle[] hitTestSpots;
 		private Rectangle appIconBounds;
+		private Rectangle maximizeButtonBounds;
 
 		WndProc( Window window ) {
 			this.window = window;
@@ -355,7 +349,7 @@ class FlatWindowsNativeWindowBorder
 
 		// invoked from native code
 		private int onNcHitTest( int x, int y, boolean isOnResizeBorder ) {
-			// scale-down mouse x/y
+			// scale-down mouse x/y because Swing coordinates/values may be scaled on a HiDPI screen
 			Point pt = scaleDown( x, y );
 			int sx = pt.x;
 			int sy = pt.y;
@@ -366,6 +360,12 @@ class FlatWindowsNativeWindowBorder
 			if( appIconBounds != null && appIconBounds.contains( sx, sy ) )
 				return HTSYSMENU;
 
+			// return HTMAXBUTTON if mouse is over maximize/restore button
+			//   - hovering mouse over HTMAXBUTTON area shows snap layouts menu on Windows 11
+			//     https://docs.microsoft.com/en-us/windows/apps/desktop/modernize/apply-snap-layout-menu
+			if( maximizeButtonBounds != null && maximizeButtonBounds.contains( sx, sy ) )
+				return HTMAXBUTTON;
+
 			boolean isOnTitleBar = (sy < titleBarHeight);
 
 			if( isOnTitleBar ) {

flatlaf-natives/flatlaf-natives-jna/build.gradle.kts

@@ -20,6 +20,6 @@ plugins {
 
 dependencies {
 	implementation( project( ":flatlaf-core" ) )
-	implementation( "net.java.dev.jna:jna:5.7.0" )
-	implementation( "net.java.dev.jna:jna-platform:5.7.0" )
+	implementation( "net.java.dev.jna:jna:5.10.0" )
+	implementation( "net.java.dev.jna:jna-platform:5.10.0" )
 }

flatlaf-natives/flatlaf-natives-jna/src/main/java/com/formdev/flatlaf/natives/jna/windows/FlatWindowsNativeWindowBorder.java

@@ -47,7 +47,7 @@ import com.sun.jna.Pointer;
 import com.sun.jna.Structure;
 import com.sun.jna.Structure.FieldOrder;
 import com.sun.jna.platform.win32.Advapi32Util;
-import com.sun.jna.platform.win32.BaseTSD;
+import com.sun.jna.platform.win32.BaseTSD.LONG_PTR;
 import com.sun.jna.platform.win32.BaseTSD.ULONG_PTR;
 import com.sun.jna.platform.win32.GDI32;
 import com.sun.jna.platform.win32.Shell32;
@@ -77,6 +77,10 @@ import com.sun.jna.win32.W32APIOptions;
 //     https://github.com/oberth/custom-chrome
 //     https://github.com/rossy/borderless-window
 //
+//   Windows 11
+//     https://docs.microsoft.com/en-us/windows/apps/desktop/modernize/apply-snap-layout-menu
+//     https://github.com/dotnet/wpf/issues/4825#issuecomment-930442736
+//
 
 /**
  * Native window border support for Windows 10 when using custom decorations.
@@ -160,30 +164,17 @@ public class FlatWindowsNativeWindowBorder
 	}
 
 	@Override
-	public void setTitleBarHeight( Window window, int titleBarHeight ) {
+	public void updateTitleBarInfo( Window window, int titleBarHeight, List<Rectangle> hitTestSpots,
+		Rectangle appIconBounds, Rectangle maximizeButtonBounds )
+	{
 		WndProc wndProc = windowsMap.get( window );
 		if( wndProc == null )
 			return;
 
 		wndProc.titleBarHeight = titleBarHeight;
-	}
-
-	@Override
-	public void setTitleBarHitTestSpots( Window window, List<Rectangle> hitTestSpots ) {
-		WndProc wndProc = windowsMap.get( window );
-		if( wndProc == null )
-			return;
-
 		wndProc.hitTestSpots = hitTestSpots.toArray( new Rectangle[hitTestSpots.size()] );
-	}
-
-	@Override
-	public void setTitleBarAppIconBounds( Window window, Rectangle appIconBounds ) {
-		WndProc wndProc = windowsMap.get( window );
-		if( wndProc == null )
-			return;
-
 		wndProc.appIconBounds = (appIconBounds != null) ? new Rectangle( appIconBounds ) : null;
+		wndProc.maximizeButtonBounds = (maximizeButtonBounds != null) ? new Rectangle( maximizeButtonBounds ) : null;
 	}
 
 	@Override
@@ -293,7 +284,16 @@ public class FlatWindowsNativeWindowBorder
 			WM_ERASEBKGND = 0x0014,
 			WM_NCCALCSIZE = 0x0083,
 			WM_NCHITTEST = 0x0084,
+
+			WM_NCMOUSEMOVE = 0x00A0,
+			WM_NCLBUTTONDOWN = 0x00A1,
+			WM_NCLBUTTONUP = 0x00A2,
 			WM_NCRBUTTONUP = 0x00A5,
+
+			WM_MOUSEMOVE= 0x0200,
+			WM_LBUTTONDOWN = 0x0201,
+			WM_LBUTTONUP = 0x0202,
+
 			WM_DWMCOLORIZATIONCOLORCHANGED = 0x0320;
 
 		// WM_SIZE wParam
@@ -306,6 +306,7 @@ public class FlatWindowsNativeWindowBorder
 			HTCLIENT = 1,
 			HTCAPTION = 2,
 			HTSYSMENU = 3,
+			HTMAXBUTTON = 9,
 			HTTOP = 12;
 
 		private static final int ABS_AUTOHIDE = 0x0000001;
@@ -328,13 +329,15 @@ public class FlatWindowsNativeWindowBorder
 
 		private Window window;
 		private final HWND hwnd;
-		private final BaseTSD.LONG_PTR defaultWndProc;
+		private final LONG_PTR defaultWndProc;
 		private int wmSizeWParam = -1;
 		private HBRUSH background;
 
+		// Swing coordinates/values may be scaled on a HiDPI screen
 		private int titleBarHeight;
 		private Rectangle[] hitTestSpots;
 		private Rectangle appIconBounds;
+		private Rectangle maximizeButtonBounds;
 
 		WndProc( Window window ) {
 			this.window = window;
@@ -427,6 +430,26 @@ public class FlatWindowsNativeWindowBorder
 				case WM_NCHITTEST:
 					return WmNcHitTest( hwnd, uMsg, wParam, lParam );
 
+				case WM_NCMOUSEMOVE:
+					// if mouse is moved over some non-client areas,
+					// send it also to the client area to allow Swing to process it
+					// (required for Windows 11 maximize button)
+					if( wParam.longValue() == HTMAXBUTTON || wParam.longValue() == HTCAPTION || wParam.longValue() == HTSYSMENU )
+						sendMessageToClientArea( hwnd, WM_MOUSEMOVE, lParam );
+					break;
+
+				case WM_NCLBUTTONDOWN:
+				case WM_NCLBUTTONUP:
+					// if left mouse was pressed/released over maximize button,
+					// send it also to the client area to allow Swing to process it
+					// (required for Windows 11 maximize button)
+					if( wParam.shortValue() == HTMAXBUTTON ) {
+						int uClientMsg = (uMsg == WM_NCLBUTTONDOWN) ? WM_LBUTTONDOWN : WM_LBUTTONUP;
+						sendMessageToClientArea( hwnd, uClientMsg, lParam );
+						return new LRESULT( 0 );
+					}
+					break;
+
 				case WM_NCRBUTTONUP:
 					if( wParam.longValue() == HTCAPTION || wParam.longValue() == HTSYSMENU )
 						openSystemMenu( hwnd, GET_X_LPARAM( lParam ), GET_Y_LPARAM( lParam ) );
@@ -522,7 +545,7 @@ public class FlatWindowsNativeWindowBorder
 
 			boolean isMaximized = User32Ex.INSTANCE.IsZoomed( hwnd );
 			if( isMaximized && !isFullscreen() ) {
-				// When a window is maximized, its size is actually a little bit more
+				// When a window is maximized, its size is actually a little bit larger
 				// than the monitor's work area. The window is positioned and sized in
 				// such a way that the resize handles are outside of the monitor and
 				// then the window is clipped to the monitor so that the resize handle
@@ -574,15 +597,12 @@ public class FlatWindowsNativeWindowBorder
 			if( lResult.longValue() != HTCLIENT )
 				return lResult;
 
-			// get window rectangle needed to convert mouse x/y from screen to window coordinates
-			RECT rcWindow = new RECT();
-			User32.INSTANCE.GetWindowRect( hwnd, rcWindow );
-
 			// get mouse x/y in window coordinates
-			int x = GET_X_LPARAM( lParam ) - rcWindow.left;
-			int y = GET_Y_LPARAM( lParam ) - rcWindow.top;
+			LRESULT xy = screen2windowCoordinates( hwnd, lParam );
+			int x = GET_X_LPARAM( xy );
+			int y = GET_Y_LPARAM( xy );
 
-			// scale-down mouse x/y
+			// scale-down mouse x/y because Swing coordinates/values may be scaled on a HiDPI screen
 			Point pt = scaleDown( x, y );
 			int sx = pt.x;
 			int sy = pt.y;
@@ -593,6 +613,12 @@ public class FlatWindowsNativeWindowBorder
 			if( appIconBounds != null && appIconBounds.contains( sx, sy ) )
 				return new LRESULT( HTSYSMENU );
 
+			// return HTMAXBUTTON if mouse is over maximize/restore button
+			//   - hovering mouse over HTMAXBUTTON area shows snap layouts menu on Windows 11
+			//     https://docs.microsoft.com/en-us/windows/apps/desktop/modernize/apply-snap-layout-menu
+			if( maximizeButtonBounds != null && maximizeButtonBounds.contains( sx, sy ) )
+				return new LRESULT( HTMAXBUTTON );
+
 			int resizeBorderHeight = getResizeHandleHeight();
 			boolean isOnResizeBorder = (y < resizeBorderHeight) &&
 				(User32.INSTANCE.GetWindowLong( hwnd, GWL_STYLE ) & WS_THICKFRAME) != 0;
@@ -612,6 +638,21 @@ public class FlatWindowsNativeWindowBorder
 			return new LRESULT( isOnResizeBorder ? HTTOP : HTCLIENT );
 		}
 
+		/**
+		 * Converts screen coordinates to window coordinates.
+		 */
+		private LRESULT screen2windowCoordinates( HWND hwnd, LPARAM lParam ) {
+			// get window rectangle needed to convert mouse x/y from screen to window coordinates
+			RECT rcWindow = new RECT();
+			User32.INSTANCE.GetWindowRect( hwnd, rcWindow );
+
+			// get mouse x/y in window coordinates
+			int x = GET_X_LPARAM( lParam ) - rcWindow.left;
+			int y = GET_Y_LPARAM( lParam ) - rcWindow.top;
+
+			return new LRESULT( MAKELONG( x, y ) );
+		}
+
 		/**
 		 * Returns the height of the little space at the top of the window used to
 		 * resize the window.
@@ -678,7 +719,7 @@ public class FlatWindowsNativeWindowBorder
 		 *
 		 * https://docs.microsoft.com/en-us/windows/win32/inputdev/wm-nchittest#remarks
 		 */
-		private int GET_X_LPARAM( LPARAM lParam ) {
+		private int GET_X_LPARAM( LONG_PTR lParam ) {
 			return (short) (lParam.longValue() & 0xffff);
 		}
 
@@ -688,10 +729,17 @@ public class FlatWindowsNativeWindowBorder
 		 *
 		 * https://docs.microsoft.com/en-us/windows/win32/inputdev/wm-nchittest#remarks
 		 */
-		private int GET_Y_LPARAM( LPARAM lParam ) {
+		private int GET_Y_LPARAM( LONG_PTR lParam ) {
 			return (short) ((lParam.longValue() >> 16) & 0xffff);
 		}
 
+		/**
+		 * Same implementation as MAKELONG(wLow, wHigh) macro in windef.h.
+		 */
+		private long MAKELONG( int low, int high ) {
+			return (low & 0xffff) | ((high & 0xffff) << 16);
+		}
+
 		/**
 		 * Same implementation as RGB(r,g,b) macro in wingdi.h.
 		 */
@@ -699,6 +747,14 @@ public class FlatWindowsNativeWindowBorder
 			return new DWORD( (r & 0xff) | ((g & 0xff) << 8) | ((b & 0xff) << 16) );
 		}
 
+		private void sendMessageToClientArea( HWND hwnd, int uMsg, LPARAM lParam ) {
+			// get mouse x/y in window coordinates
+			LRESULT xy = screen2windowCoordinates( hwnd, lParam );
+
+			// send message
+			User32.INSTANCE.SendMessage( hwnd, uMsg, new WPARAM(), new LPARAM( xy.longValue() ) );
+		}
+
 		/**
 		 * Opens the window's system menu.
 		 * The system menu is the menu that opens when the user presses Alt+Space or

flatlaf-natives/flatlaf-natives-windows/src/main/cpp/FlatWndProc.cpp

@@ -215,6 +215,26 @@ LRESULT CALLBACK FlatWndProc::WindowProc( HWND hwnd, UINT uMsg, WPARAM wParam, L
 		case WM_NCHITTEST:
 			return WmNcHitTest( hwnd, uMsg, wParam, lParam );
 
+		case WM_NCMOUSEMOVE:
+			// if mouse is moved over some non-client areas,
+			// send it also to the client area to allow Swing to process it
+			// (required for Windows 11 maximize button)
+			if( wParam == HTMAXBUTTON || wParam == HTCAPTION || wParam == HTSYSMENU )
+				sendMessageToClientArea( hwnd, WM_MOUSEMOVE, lParam );
+			break;
+
+		case WM_NCLBUTTONDOWN:
+		case WM_NCLBUTTONUP:
+			// if left mouse was pressed/released over maximize button,
+			// send it also to the client area to allow Swing to process it
+			// (required for Windows 11 maximize button)
+			if( wParam == HTMAXBUTTON ) {
+				int uClientMsg = (uMsg == WM_NCLBUTTONDOWN) ? WM_LBUTTONDOWN : WM_LBUTTONUP;
+				sendMessageToClientArea( hwnd, uClientMsg, lParam );
+				return 0;
+			}
+			break;
+
 		case WM_NCRBUTTONUP:
 			if( wParam == HTCAPTION || wParam == HTSYSMENU )
 				openSystemMenu( hwnd, GET_X_LPARAM( lParam ), GET_Y_LPARAM( lParam ) );
@@ -305,7 +325,7 @@ LRESULT FlatWndProc::WmNcCalcSize( HWND hwnd, int uMsg, WPARAM wParam, LPARAM lP
 
 	bool isMaximized = ::IsZoomed( hwnd );
 	if( isMaximized && !isFullscreen() ) {
-		// When a window is maximized, its size is actually a little bit more
+		// When a window is maximized, its size is actually a little bit larger
 		// than the monitor's work area. The window is positioned and sized in
 		// such a way that the resize handles are outside of the monitor and
 		// then the window is clipped to the monitor so that the resize handle
@@ -354,6 +374,22 @@ LRESULT FlatWndProc::WmNcHitTest( HWND hwnd, int uMsg, WPARAM wParam, LPARAM lPa
 	if( lResult != HTCLIENT )
 		return lResult;
 
+	// get mouse x/y in window coordinates
+	LRESULT xy = screen2windowCoordinates( hwnd, lParam );
+	int x = GET_X_LPARAM( xy );
+	int y = GET_Y_LPARAM( xy );
+
+	int resizeBorderHeight = getResizeHandleHeight();
+	bool isOnResizeBorder = (y < resizeBorderHeight) &&
+		(::GetWindowLong( hwnd, GWL_STYLE ) & WS_THICKFRAME) != 0;
+
+	return onNcHitTest( x, y, isOnResizeBorder );
+}
+
+/**
+ * Converts screen coordinates to window coordinates.
+ */
+LRESULT FlatWndProc::screen2windowCoordinates( HWND hwnd, LPARAM lParam ) {
 	// get window rectangle needed to convert mouse x/y from screen to window coordinates
 	RECT rcWindow;
 	::GetWindowRect( hwnd, &rcWindow );
@@ -362,11 +398,7 @@ LRESULT FlatWndProc::WmNcHitTest( HWND hwnd, int uMsg, WPARAM wParam, LPARAM lPa
 	int x = GET_X_LPARAM( lParam ) - rcWindow.left;
 	int y = GET_Y_LPARAM( lParam ) - rcWindow.top;
 
-	int resizeBorderHeight = getResizeHandleHeight();
-	bool isOnResizeBorder = (y < resizeBorderHeight) &&
-		(::GetWindowLong( hwnd, GWL_STYLE ) & WS_THICKFRAME) != 0;
-
-	return onNcHitTest( x, y, isOnResizeBorder );
+	return MAKELONG( x, y );
 }
 
 /**
@@ -429,6 +461,14 @@ JNIEnv* FlatWndProc::getEnv() {
 	return env;
 }
 
+void FlatWndProc::sendMessageToClientArea( HWND hwnd, int uMsg, LPARAM lParam ) {
+	// get mouse x/y in window coordinates
+	LRESULT xy = screen2windowCoordinates( hwnd, lParam );
+
+	// send message
+	::SendMessage( hwnd, uMsg, 0, xy );
+}
+
 /**
  * Opens the window's system menu.
  * The system menu is the menu that opens when the user presses Alt+Space or

flatlaf-natives/flatlaf-natives-windows/src/main/cpp/FlatWndProc.h

@@ -54,6 +54,7 @@ private:
 	LRESULT WmNcCalcSize( HWND hwnd, int uMsg, WPARAM wParam, LPARAM lParam );
 	LRESULT WmNcHitTest( HWND hwnd, int uMsg, WPARAM wParam, LPARAM lParam );
 
+	LRESULT screen2windowCoordinates( HWND hwnd, LPARAM lParam );
 	int getResizeHandleHeight();
 	bool hasAutohideTaskbar( UINT edge, RECT rcMonitor );
 	BOOL isFullscreen();
@@ -61,6 +62,7 @@ private:
 	void fireStateChangedLaterOnce();
 	JNIEnv* getEnv();
 
+	void sendMessageToClientArea( HWND hwnd, int uMsg, LPARAM lParam );
 	void openSystemMenu( HWND hwnd, int x, int y );
 	void setMenuItemState( HMENU systemMenu, int item, bool enabled );
 

flatlaf-natives/flatlaf-natives-windows/src/main/headers/com_formdev_flatlaf_ui_FlatWindowsNativeWindowBorder_WndProc.h

@@ -13,6 +13,8 @@ extern "C" {
 #define com_formdev_flatlaf_ui_FlatWindowsNativeWindowBorder_WndProc_HTCAPTION 2L
 #undef com_formdev_flatlaf_ui_FlatWindowsNativeWindowBorder_WndProc_HTSYSMENU
 #define com_formdev_flatlaf_ui_FlatWindowsNativeWindowBorder_WndProc_HTSYSMENU 3L
+#undef com_formdev_flatlaf_ui_FlatWindowsNativeWindowBorder_WndProc_HTMAXBUTTON
+#define com_formdev_flatlaf_ui_FlatWindowsNativeWindowBorder_WndProc_HTMAXBUTTON 9L
 #undef com_formdev_flatlaf_ui_FlatWindowsNativeWindowBorder_WndProc_HTTOP
 #define com_formdev_flatlaf_ui_FlatWindowsNativeWindowBorder_WndProc_HTTOP 12L
 /*