diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeWindowBorder.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeWindowBorder.java
index 4d4afab1..86bc8dc4 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeWindowBorder.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeWindowBorder.java
@@ -125,6 +125,10 @@ public class FlatNativeWindowBorder
 			// enable native window border for window
 			setHasCustomDecoration( frame, true );
 
+			// avoid double window title bar if enabling native window border failed
+			if( !hasCustomDecoration( frame ) )
+				return;
+
 			// enable Swing window decoration
 			rootPane.setWindowDecorationStyle( JRootPane.FRAME );
 
@@ -143,6 +147,10 @@ public class FlatNativeWindowBorder
 			// enable native window border for window
 			setHasCustomDecoration( dialog, true );
 
+			// avoid double window title bar if enabling native window border failed
+			if( !hasCustomDecoration( dialog ) )
+				return;
+
 			// enable Swing window decoration
 			rootPane.setWindowDecorationStyle( JRootPane.PLAIN_DIALOG );
 		}
diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowsNativeWindowBorder.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowsNativeWindowBorder.java
index 4b909a05..87977450 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowsNativeWindowBorder.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowsNativeWindowBorder.java
@@ -308,6 +308,8 @@ class FlatWindowsNativeWindowBorder
 			this.window = window;
 
 			hwnd = installImpl( window );
+			if( hwnd == 0 )
+				return;
 
 			// remove the OS window title bar
 			if( window instanceof JFrame && ((JFrame)window).getExtendedState() != 0 ) {