diff --git a/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderRenderer.java b/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderRenderer.java
index 21e45f37dee..e736a22b295 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderRenderer.java	
+++ b/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderRenderer.java	
@@ -747,7 +747,10 @@ private void drawDirtyIndicator(GC gc, Rectangle closeRect, boolean selected) {
 		if (!selected) {
 			gc.setAlpha(140);
 		}
+		int originalAntialias = gc.getAntialias();
+		gc.setAntialias(SWT.ON);
 		gc.fillOval(x, y, diameter, diameter);
+		gc.setAntialias(originalAntialias);
 		gc.setAlpha(originalAlpha);
 		gc.setBackground(originalBackground);
 	}