diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatScrollBarUI.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatScrollBarUI.java
index 3f58f96f..27760686 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatScrollBarUI.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatScrollBarUI.java
@@ -142,6 +142,12 @@ public class FlatScrollBarUI
 		buttonDisabledArrowColor = UIManager.getColor( "ScrollBar.buttonDisabledArrowColor" );
 		hoverButtonBackground = UIManager.getColor( "ScrollBar.hoverButtonBackground" );
 		pressedButtonBackground = UIManager.getColor( "ScrollBar.pressedButtonBackground" );
+
+		// fallback (e.g. when used in NetBeans GUI builder)
+		if( trackInsets == null )
+			trackInsets = new Insets( 0, 0, 0, 0 );
+		if( thumbInsets == null )
+			thumbInsets = new Insets( 0, 0, 0, 0 );
 	}
 
 	@Override