From bf8cc268cc17575d0796b7931384aea8faeed3a8 Mon Sep 17 00:00:00 2001
From: Karl Tauber <karl@jformdesigner.com>
Date: Tue, 17 Dec 2019 11:35:16 +0100
Subject: [PATCH] on Mac show mnemonics only when `Ctrl` and `Alt` keys are
 pressed (issue #4)

---
 CHANGELOG.md                                  |  2 ++
 .../java/com/formdev/flatlaf/FlatLaf.java     | 26 ++++++++++++++-----
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe2b4172..e4bd9dcc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,8 @@ FlatLaf Change Log
   pressing focused button with <kbd>Enter</kbd> key (as in Windows LaF).
 - Fixed clipped borders at 125%, 150% and 175% scaling when outer focus width is
   zero (default in "Flat Light" and "Flat Dark" themes).
+- On Mac show mnemonics only when <kbd>Ctrl</kbd> and <kbd>Alt</kbd> keys are
+  pressed. (issue #4)
 
 
 ## 0.21
diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java
index 92d62dbe..b1c99104 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java
@@ -61,7 +61,7 @@ public abstract class FlatLaf
 	private PropertyChangeListener desktopPropertyListener;
 
 	private KeyEventPostProcessor mnemonicListener;
-	private static boolean altKeyPressed;
+	private static boolean showMnemonics;
 
 	private Consumer<UIDefaults> postInitialization;
 
@@ -113,8 +113,7 @@ public abstract class FlatLaf
 
 		// add mnemonic listener
 		mnemonicListener = e -> {
-			if( e.getKeyCode() == KeyEvent.VK_ALT )
-				altKeyChanged( e.getID() == KeyEvent.KEY_PRESSED );
+			checkShowMnemonics( e );
 			return false;
 		};
 		KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventPostProcessor( mnemonicListener );
@@ -357,14 +356,27 @@ public abstract class FlatLaf
 	}
 
 	public static boolean isShowMnemonics() {
-		return altKeyPressed || !UIManager.getBoolean( "Component.hideMnemonics" );
+		return showMnemonics || !UIManager.getBoolean( "Component.hideMnemonics" );
 	}
 
-	private static void altKeyChanged( boolean pressed ) {
-		if( pressed == altKeyPressed )
+	private static void checkShowMnemonics( KeyEvent e ) {
+		int keyCode = e.getKeyCode();
+		if( SystemInfo.IS_MAC ) {
+			// Ctrl+Alt keys must be pressed on Mac
+			if( keyCode == KeyEvent.VK_CONTROL || keyCode == KeyEvent.VK_ALT )
+				showMnemonics( e.getID() == KeyEvent.KEY_PRESSED && e.isControlDown() && e.isAltDown() );
+		} else {
+			// Alt key must be pressed on Windows and Linux
+			if( keyCode == KeyEvent.VK_ALT )
+				showMnemonics( e.getID() == KeyEvent.KEY_PRESSED );
+		}
+	}
+
+	private static void showMnemonics( boolean show ) {
+		if( show == showMnemonics )
 			return;
 
-		altKeyPressed = pressed;
+		showMnemonics = show;
 
 		// check whether it is necessary to repaint
 		if( !UIManager.getBoolean( "Component.hideMnemonics" ) )