diff --git a/CHANGELOG.md b/CHANGELOG.md
index efc57e92..dda9b960 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@ FlatLaf Change Log
 
 #### New features and improvements
 
+- ToggleButton: Made the underline placement of tab-style toggle buttons
+  configurable. (PR #530; issue #529)
 - Added spanish translation. (PR #525)
 
 #### Fixed bugs
diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatClientProperties.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatClientProperties.java
index 38e3560c..18c64934 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatClientProperties.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatClientProperties.java
@@ -996,19 +996,13 @@ public interface FlatClientProperties
 	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JToggleButton}<br>
 	 * <strong>Value type</strong> {@link java.lang.Integer}<br>
-	 * <strong>Default value</strong> {@link SwingConstants#BOTTOM}<br>
 	 * <strong>SupportedValues:</strong>
-	 * <table>
-	 * <thead>
-	 *     <tr><td>Placement</td><td>Constant</td><td>Value</td></tr>
-	 * </thead>
-	 * <tbody>
-	 *     <tr><td>TOP</td><td>{@link SwingConstants#TOP}</td><td>{@value SwingConstants#TOP}</td></tr>
-	 *     <tr><td>LEFT</td><td>{@link SwingConstants#LEFT}</td><td>{@value SwingConstants#LEFT}</td></tr>
-	 *     <tr><td>BOTTOM</td><td>{@link SwingConstants#BOTTOM}</td><td>{@value SwingConstants#BOTTOM}</td></tr>
-	 *     <tr><td>RIGHT</td><td>{@link SwingConstants#RIGHT}</td><td>{@value SwingConstants#RIGHT}</td></tr>
-	 * </tbody>
-	 * </table>
+	 *     {@link SwingConstants#BOTTOM} (default)
+	 *     {@link SwingConstants#TOP},
+	 *     {@link SwingConstants#LEFT} or
+	 *     {@link SwingConstants#RIGHT}
+	 *
+	 * @since 2.3
 	 */
 	String TAB_BUTTON_UNDERLINE_PLACEMENT = "JToggleButton.tab.underlinePlacement";
 
diff --git a/flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/components/FlatToggleButton.java b/flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/components/FlatToggleButton.java
index 3190223b..b8eca017 100644
--- a/flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/components/FlatToggleButton.java
+++ b/flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/components/FlatToggleButton.java
@@ -120,6 +120,8 @@ public class FlatToggleButton
 	 * Returns placement of underline if toggle button type is {@link ButtonType#tab}.
 	 * If underline placement is not specified, returns {@link #BOTTOM} as the default
 	 * value.
+	 *
+	 * @since 2.3
 	 */
 	public int getTabUnderlinePlacement() {
 		return getClientPropertyInt( TAB_BUTTON_UNDERLINE_PLACEMENT, BOTTOM );
@@ -130,20 +132,21 @@ public class FlatToggleButton
 	 *
 	 * @param placement  One of the following constants defined in SwingConstants:
 	 *                   {@link #TOP}, {@link #LEFT}, {@link #BOTTOM}, or {@link #RIGHT}.
+	 * @since 2.3
 	 */
 	public void setTabUnderlinePlacement( int placement ) {
-		putClientProperty( TAB_BUTTON_UNDERLINE_PLACEMENT, (placement < 0 || placement >= RIGHT) ? null : placement);
+		putClientProperty( TAB_BUTTON_UNDERLINE_PLACEMENT, (placement >= 0) ? placement : null );
 	}
 
 	/**
-	 * Returns height of underline if toggle button type is {@link ButtonType#tab}.
+	 * Returns thickness of underline if toggle button type is {@link ButtonType#tab}.
 	 */
 	public int getTabUnderlineHeight() {
 		return getClientPropertyInt( TAB_BUTTON_UNDERLINE_HEIGHT, "ToggleButton.tab.underlineHeight" );
 	}
 
 	/**
-	 * Specifies height of underline if toggle button type is {@link ButtonType#tab}.
+	 * Specifies thickness of underline if toggle button type is {@link ButtonType#tab}.
 	 */
 	public void setTabUnderlineHeight( int tabUnderlineHeight ) {
 		putClientProperty( TAB_BUTTON_UNDERLINE_HEIGHT, (tabUnderlineHeight >= 0) ? tabUnderlineHeight : null );