diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d15eca2..3e1a7501 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -60,6 +60,15 @@ FlatLaf Change Log
   - `FlatSVGUtils`: Support loading SVG from `URL` (for JPMS). (issue #325)
 
 
+## 1.6.4
+
+#### Fixed bugs
+
+- ComboBox: Fixed regression in FlatLaf 1.6.3 that makes selected item invisible
+  in popup list if `DefaultListCellRenderer` is used as renderer. If using
+  default renderer, it works. (issue #426)
+
+
 ## 1.6.3
 
 #### Fixed bugs
diff --git a/build.gradle.kts b/build.gradle.kts
index d9b018d8..5857ac40 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-val releaseVersion = "1.6.3"
+val releaseVersion = "1.6.4"
 val developmentVersion = "2.0-SNAPSHOT"
 
 version = if( java.lang.Boolean.getBoolean( "release" ) ) releaseVersion else developmentVersion
diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatComboBoxUI.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatComboBoxUI.java
index e6cc5773..37639d94 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatComboBoxUI.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatComboBoxUI.java
@@ -591,11 +591,8 @@ public class FlatComboBoxUI
 		// make renderer component temporary non-opaque to avoid that renderer paints
 		// background outside of border if combobox uses larger arc for edges
 		// (e.g. FlatClientProperties.COMPONENT_ROUND_RECT is true)
-		boolean oldOpaque = true;
-		if( c instanceof JComponent ) {
-			oldOpaque = ((JComponent)c).isOpaque();
+		if( c instanceof JComponent )
 			((JComponent)c).setOpaque( false );
-		}
 
 		boolean shouldValidate = (c instanceof JPanel);
 
@@ -604,7 +601,7 @@ public class FlatComboBoxUI
 		paddingBorder.uninstall();
 
 		if( c instanceof JComponent )
-			((JComponent)c).setOpaque( oldOpaque );
+			((JComponent)c).setOpaque( true );
 	}
 
 	@Override
diff --git a/flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatComponentsTest.java b/flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatComponentsTest.java
index d63e1fd4..4756b04f 100644
--- a/flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatComponentsTest.java
+++ b/flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatComponentsTest.java
@@ -1621,6 +1621,7 @@ public class FlatComponentsTest
 //		customRenderer.setBorder( new LineBorder( Color.red ) );
 //		comboBox1.setRenderer( customRenderer );
 //		comboBox3.setRenderer( customRenderer );
+//		comboBox5.setRenderer( new DefaultListCellRenderer() );
 
 		// for testing issue #382
 //		spinner1.setModel( new SpinnerNumberModel( 0, null, 100, 1 ) );