diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeMacLibrary.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeMacLibrary.java
index 2a1b24c3..3799bfd9 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeMacLibrary.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeMacLibrary.java
@@ -23,6 +23,20 @@ import java.awt.Window;
  * <p>
  * <b>Note</b>: This is private API. Do not use!
  *
+ * <h2>Methods that use windows as parameter</h2>
+ *
+ * For all methods that accept a {@link java.awt.Window} as parameter,
+ * the underlying macOS window must be already created,
+ * otherwise the method fails. You can use following to ensure this:
+ * <pre>{@code
+ * if( !window.isDisplayable() )
+ *     window.addNotify();
+ * }</pre>
+ * or invoke the method after packing the window. E.g.
+ * <pre>{@code
+ * window.pack();
+ * }</pre>
+ *
  * @author Karl Tauber
  * @since 3.3
  */
@@ -38,22 +52,5 @@ public class FlatNativeMacLibrary
 		return FlatNativeLibrary.isLoaded();
 	}
 
-	/**
-	 * Gets the macOS window pointer (NSWindow) for the given Swing window.
-	 * <p>
-	 * Note that the underlying macOS window must be already created,
-	 * otherwise this method returns zero. Use following to ensure this:
-	 * <pre>{@code
-	 * if( !window.isDisplayable() )
-	 *     window.addNotify();
-	 * }</pre>
-	 * or invoke this method after packing the window. E.g.
-	 * <pre>{@code
-	 * window.pack();
-	 * long windowPtr = getWindowPtr( window );
-	 * }</pre>
-	 */
-	public native static long getWindowPtr( Window window );
-
-	public native static void setWindowRoundedBorder( long windowPtr, float radius, float borderWidth, int borderColor );
+	public native static boolean setWindowRoundedBorder( Window window, float radius, float borderWidth, int borderColor );
 }
diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPopupFactory.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPopupFactory.java
index 8aa636f0..9039c28d 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPopupFactory.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPopupFactory.java
@@ -324,13 +324,6 @@ public class FlatPopupFactory
 		if( !popupWindow.isDisplayable() )
 			popupWindow.addNotify();
 
-		// get native window handle/pointer
-		long hwnd = SystemInfo.isWindows
-			? FlatNativeWindowsLibrary.getHWND( popupWindow )
-			: FlatNativeMacLibrary.getWindowPtr( popupWindow );
-		if( hwnd == 0 )
-			return;
-
 		int borderCornerRadius = getBorderCornerRadius( owner, contents );
 		float borderWidth = getRoundedBorderWidth( owner, contents );
 
@@ -353,6 +346,9 @@ public class FlatPopupFactory
 		}
 
 		if( SystemInfo.isWindows ) {
+			// get native window handle
+			long hwnd = FlatNativeWindowsLibrary.getHWND( popupWindow );
+
 			// set corner preference
 			int cornerPreference = (borderCornerRadius <= 4)
 				? FlatNativeWindowsLibrary.DWMWCP_ROUNDSMALL  // 4px
@@ -366,7 +362,7 @@ public class FlatPopupFactory
 				borderWidth = 0;
 
 			// set corner radius, border width and color
-			FlatNativeMacLibrary.setWindowRoundedBorder( hwnd, borderCornerRadius,
+			FlatNativeMacLibrary.setWindowRoundedBorder( popupWindow, borderCornerRadius,
 				borderWidth, (borderColor != null) ? borderColor.getRGB() : 0 );
 		}
 	}
diff --git a/flatlaf-core/src/main/resources/com/formdev/flatlaf/natives/libflatlaf-macos-arm64.dylib b/flatlaf-core/src/main/resources/com/formdev/flatlaf/natives/libflatlaf-macos-arm64.dylib
old mode 100644
new mode 100755
index 6094c831..e29df3b1
Binary files a/flatlaf-core/src/main/resources/com/formdev/flatlaf/natives/libflatlaf-macos-arm64.dylib and b/flatlaf-core/src/main/resources/com/formdev/flatlaf/natives/libflatlaf-macos-arm64.dylib differ
diff --git a/flatlaf-core/src/main/resources/com/formdev/flatlaf/natives/libflatlaf-macos-x86_64.dylib b/flatlaf-core/src/main/resources/com/formdev/flatlaf/natives/libflatlaf-macos-x86_64.dylib
old mode 100644
new mode 100755
index a15d4876..bb1c221c
Binary files a/flatlaf-core/src/main/resources/com/formdev/flatlaf/natives/libflatlaf-macos-x86_64.dylib and b/flatlaf-core/src/main/resources/com/formdev/flatlaf/natives/libflatlaf-macos-x86_64.dylib differ
diff --git a/flatlaf-natives/flatlaf-natives-macos/build.gradle.kts b/flatlaf-natives/flatlaf-natives-macos/build.gradle.kts
index b6b24745..322b1998 100644
--- a/flatlaf-natives/flatlaf-natives-macos/build.gradle.kts
+++ b/flatlaf-natives/flatlaf-natives-macos/build.gradle.kts
@@ -81,7 +81,7 @@ tasks {
 		val nativesDir = project( ":flatlaf-core" ).projectDir.resolve( "src/main/resources/com/formdev/flatlaf/natives" )
 		val isARM64 = name.contains( "Arm64" )
 		val minOs = if( isARM64 ) minOsARM64 else minOsX86_64
-		val libraryName = if( isARM64 ) "flatlaf-macos-arm64.dylib" else "flatlaf-macos-x86_64.dylib"
+		val libraryName = if( isARM64 ) "libflatlaf-macos-arm64.dylib" else "libflatlaf-macos-x86_64.dylib"
 
 		linkerArgs.addAll( toolChain.map {
 			when( it ) {
@@ -91,14 +91,17 @@ tasks {
 		} )
 
 		doLast {
+			// sign shared library
+//			exec { commandLine( "codesign", "-s", "FormDev Software GmbH", "--timestamp", "${linkedFile.asFile.get()}" ) }
+
 			// copy shared library to flatlaf-core resources
 			copy {
 				from( linkedFile )
 				into( nativesDir )
-				rename( "flatlaf-natives-macos.dylib", libraryName )
+				rename( "libflatlaf-natives-macos.dylib", libraryName )
 			}
 
-///*dump
+/*dump
 			val dylib = linkedFile.asFile.get()
 			val dylibDir = dylib.parent
 			exec { commandLine( "size", dylib ) }
@@ -123,7 +126,7 @@ tasks {
 			}
 			exec { commandLine( "objdump", "--disassemble-all", dylib ); standardOutput = FileOutputStream( "$dylibDir/disassemble.txt" ) }
 			exec { commandLine( "objdump", "--full-contents", dylib ); standardOutput = FileOutputStream( "$dylibDir/full-contents.txt" ) }
-//dump*/
+dump*/
 		}
 	}
 }
diff --git a/flatlaf-natives/flatlaf-natives-macos/src/main/headers/JNIUtils.h b/flatlaf-natives/flatlaf-natives-macos/src/main/headers/JNIUtils.h
index 8e5be892..2de80956 100644
--- a/flatlaf-natives/flatlaf-natives-macos/src/main/headers/JNIUtils.h
+++ b/flatlaf-natives/flatlaf-natives-macos/src/main/headers/JNIUtils.h
@@ -23,9 +23,9 @@
  */
 
 
-// from JNFJNI.h
+// from jlong_md.h
 #ifndef jlong_to_ptr
-#define jlong_to_ptr(a) ((void *)(uintptr_t)(a))
+  #define jlong_to_ptr(a) ((void*)(a))
 #endif
 
 
@@ -39,3 +39,6 @@
  				[ex name], [ex reason], [ex userInfo], [ex callStackSymbols] ); \
  		} \
 	}
+
+
+jfieldID getFieldID( JNIEnv *env, const char* className, const char* fieldName, const char* fieldSignature );
diff --git a/flatlaf-natives/flatlaf-natives-macos/src/main/headers/com_formdev_flatlaf_ui_FlatNativeMacLibrary.h b/flatlaf-natives/flatlaf-natives-macos/src/main/headers/com_formdev_flatlaf_ui_FlatNativeMacLibrary.h
index f4d55eed..f5bcd35b 100644
--- a/flatlaf-natives/flatlaf-natives-macos/src/main/headers/com_formdev_flatlaf_ui_FlatNativeMacLibrary.h
+++ b/flatlaf-natives/flatlaf-natives-macos/src/main/headers/com_formdev_flatlaf_ui_FlatNativeMacLibrary.h
@@ -7,21 +7,13 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
-/*
- * Class:     com_formdev_flatlaf_ui_FlatNativeMacLibrary
- * Method:    getWindowPtr
- * Signature: (Ljava/awt/Window;)J
- */
-JNIEXPORT jlong JNICALL Java_com_formdev_flatlaf_ui_FlatNativeMacLibrary_getWindowPtr
-  (JNIEnv *, jclass, jobject);
-
 /*
  * Class:     com_formdev_flatlaf_ui_FlatNativeMacLibrary
  * Method:    setWindowRoundedBorder
- * Signature: (JFFI)V
+ * Signature: (Ljava/awt/Window;FFI)Z
  */
-JNIEXPORT void JNICALL Java_com_formdev_flatlaf_ui_FlatNativeMacLibrary_setWindowRoundedBorder
-  (JNIEnv *, jclass, jlong, jfloat, jfloat, jint);
+JNIEXPORT jboolean JNICALL Java_com_formdev_flatlaf_ui_FlatNativeMacLibrary_setWindowRoundedBorder
+  (JNIEnv *, jclass, jobject, jfloat, jfloat, jint);
 
 #ifdef __cplusplus
 }
diff --git a/flatlaf-natives/flatlaf-natives-macos/src/main/objcpp/JNIUtils.mm b/flatlaf-natives/flatlaf-natives-macos/src/main/objcpp/JNIUtils.mm
new file mode 100644
index 00000000..7c4e798d
--- /dev/null
+++ b/flatlaf-natives/flatlaf-natives-macos/src/main/objcpp/JNIUtils.mm
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2023 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import <stdlib.h>
+#import "JNIUtils.h"
+
+/**
+ * @author Karl Tauber
+ */
+
+jfieldID getFieldID( JNIEnv *env, const char* className, const char* fieldName, const char* fieldSignature ) {
+//	NSLog( @"getFieldID %s %s %s", className, fieldName, fieldSignature );
+
+	jclass cls = env->FindClass( className );
+	if( cls == NULL ) {
+		NSLog( @"FlatLaf: failed to lookup class '%s'", className );
+		env->ExceptionDescribe(); // print stack trace
+		env->ExceptionClear();
+		return NULL;
+	}
+
+	jfieldID fieldID = env->GetFieldID( cls, fieldName, fieldSignature );
+	if( fieldID == NULL ) {
+		NSLog( @"FlatLaf: failed to lookup field '%s' of type '%s' in class '%s'", fieldName, fieldSignature, className );
+		env->ExceptionDescribe(); // print stack trace
+		env->ExceptionClear();
+		return NULL;
+	}
+
+	return fieldID;
+}
diff --git a/flatlaf-natives/flatlaf-natives-macos/src/main/objcpp/MacWindow.mm b/flatlaf-natives/flatlaf-natives-macos/src/main/objcpp/MacWindow.mm
index de0e8876..5d81a51c 100644
--- a/flatlaf-natives/flatlaf-natives-macos/src/main/objcpp/MacWindow.mm
+++ b/flatlaf-natives/flatlaf-natives-macos/src/main/objcpp/MacWindow.mm
@@ -24,67 +24,66 @@
  * @author Karl Tauber
  */
 
-extern "C"
-JNIEXPORT jlong JNICALL Java_com_formdev_flatlaf_ui_FlatNativeMacLibrary_getWindowPtr
-	( JNIEnv* env, jclass cls, jobject window )
-{
+NSWindow* getNSWindow( JNIEnv* env, jclass cls, jobject window ) {
 	if( window == NULL )
 		return NULL;
-	
-	JNI_COCOA_ENTER()
+
+	// initialize field IDs (done only once because fields are static)
+	static jfieldID peerID = getFieldID( env, "java/awt/Component", "peer", "Ljava/awt/peer/ComponentPeer;" );
+	static jfieldID platformWindowID = getFieldID( env, "sun/lwawt/LWWindowPeer", "platformWindow", "Lsun/lwawt/PlatformWindow;" );
+	static jfieldID ptrID = getFieldID( env, "sun/lwawt/macosx/CFRetainedResource", "ptr", "J" );
+	if( peerID == NULL || platformWindowID == NULL || ptrID == NULL )
+		return NULL;
 
 	// get field java.awt.Component.peer
-	jfieldID peerID = env->GetFieldID( env->GetObjectClass( window ), "peer", "Ljava/awt/peer/ComponentPeer;" );
-	jobject peer = (peerID != NULL) ? env->GetObjectField( window, peerID ) : NULL;
+	jobject peer = env->GetObjectField( window, peerID );
 	if( peer == NULL )
 		return NULL;
 
 	// get field sun.lwawt.LWWindowPeer.platformWindow
-	jfieldID platformWindowID = env->GetFieldID( env->GetObjectClass( peer ), "platformWindow", "Lsun/lwawt/PlatformWindow;" );
-	jobject platformWindow = (platformWindowID != NULL) ? env->GetObjectField( peer, platformWindowID ) : NULL;
+	jobject platformWindow = env->GetObjectField( peer, platformWindowID );
 	if( platformWindow == NULL )
 		return NULL;
 
 	// get field sun.lwawt.macosx.CFRetainedResource.ptr
-	jfieldID ptrID = env->GetFieldID( env->GetObjectClass( platformWindow ), "ptr", "J" );
-	return (ptrID != NULL) ? env->GetLongField( platformWindow, ptrID ) : NULL;
-
-	JNI_COCOA_EXIT()
+	return (NSWindow *) jlong_to_ptr( env->GetLongField( platformWindow, ptrID ) );
 }
 
 extern "C"
-JNIEXPORT void JNICALL Java_com_formdev_flatlaf_ui_FlatNativeMacLibrary_setWindowRoundedBorder
-	( JNIEnv* env, jclass cls, jlong windowPtr, jfloat radius, jfloat borderWidth, jint borderColor )
+JNIEXPORT jboolean JNICALL Java_com_formdev_flatlaf_ui_FlatNativeMacLibrary_setWindowRoundedBorder
+	( JNIEnv* env, jclass cls, jobject window, jfloat radius, jfloat borderWidth, jint borderColor )
 {
-	if( windowPtr == 0 )
-		return;
-	
 	JNI_COCOA_ENTER()
 
+	NSWindow* nsWindow = getNSWindow( env, cls, window );
+	if( nsWindow == NULL )
+		return FALSE;
+
 	[FlatJNFRunLoop performOnMainThreadWaiting:NO withBlock:^(){
-		NSWindow* window = (NSWindow *) jlong_to_ptr( windowPtr );
+		nsWindow.hasShadow = YES;
+		nsWindow.contentView.wantsLayer = YES;
+		nsWindow.contentView.layer.cornerRadius = radius;
+		nsWindow.contentView.layer.masksToBounds = YES;
 
-		window.hasShadow = YES;
-		window.contentView.wantsLayer = YES;
-		window.contentView.layer.cornerRadius = radius;
-		window.contentView.layer.masksToBounds = YES;
-
-		window.contentView.layer.borderWidth = borderWidth;
+		nsWindow.contentView.layer.borderWidth = borderWidth;
 		if( borderWidth > 0 ) {
 			CGFloat red   = ((borderColor >> 16) & 0xff) / 255.;
 			CGFloat green = ((borderColor >> 8) & 0xff) / 255.;
 			CGFloat blue  = (borderColor & 0xff) / 255.;
 			CGFloat alpha = ((borderColor >> 24) & 0xff) / 255.;
 
-			window.contentView.layer.borderColor = [[NSColor colorWithDeviceRed:red green:green blue:blue alpha:alpha] CGColor];
+			nsWindow.contentView.layer.borderColor = [[NSColor colorWithDeviceRed:red green:green blue:blue alpha:alpha] CGColor];
 		}
 
-		window.backgroundColor = NSColor.clearColor;
-		window.opaque = NO;
+		nsWindow.backgroundColor = NSColor.clearColor;
+		nsWindow.opaque = NO;
 
-		[window.contentView.layer removeAllAnimations];
-		[window invalidateShadow];
+		[nsWindow.contentView.layer removeAllAnimations];
+		[nsWindow invalidateShadow];
 	}];
 
+	return TRUE;
+
 	JNI_COCOA_EXIT()
+	return FALSE;
 }