Left and right Control and Alt keys are distinguished using the Extended flag (the previously implemented trick only worked for KeyPress, not for KeyRelease).bug_2945130fff

1 files changed, 18 insertions, 12 deletions

diff --git a/win/tkWinKey.c b/win/tkWinKey.c
index ed546f7..10cc7b8 100644
--- a/win/tkWinKey.c
+++ b/win/tkWinKey.c
@@ -335,18 +335,24 @@ KeycodeToKeysym(
 	/*
 	 * Windows only gives us an undifferentiated VK_CONTROL code (for
 	 * example) when either Control key is pressed. To distinguish between
-	 * left and right, we have to query the state of one of the two to
-	 * determine which was actually pressed. So if the keycode indicates
-	 * Control, Shift, or Menu (the key that everybody else calls Alt), do
-	 * this extra test. If the right-side key was pressed, return the
-	 * appropriate keycode. Otherwise, we fall through and rely on the
-	 * keymap table to hold the correct keysym value.
+	 * left and right, we use the Extended flag. Indeed, the right Control
+	 * and Alt (aka Menu) keys are such extended keys (which their left
+	 * counterparts are not).
+	 * Regarding the shift case, Windows does not set the Extended flag for
+	 * the neither the left nor the right shift key. As a consequence another
+	 * way to distinguish between the two keys is to query the state of one
+	 * of the two to determine which was actually pressed. So if the keycode
+	 * indicates Shift, do this extra test. If the right-side key was
+	 * pressed, return the appropriate keycode. Otherwise, we fall through
+	 * and rely on the keymap table to hold the correct keysym value.
+	 * Note: this little trick only works for KeyPress, not for KeyRelease,
+	 * for reasons stated in bug [2945130]
 	 */
 
     case VK_CONTROL:
-	if (GetKeyState(VK_RCONTROL) & 0x80) {
-	    return XK_Control_R;
-	}
+        if (state & EXTENDED_MASK) {
+            return XK_Control_R;
+        }
 	break;
     case VK_SHIFT:
 	if (GetKeyState(VK_RSHIFT) & 0x80) {
@@ -354,9 +360,9 @@ KeycodeToKeysym(
 	}
 	break;
     case VK_MENU:
-	if (GetKeyState(VK_RMENU) & 0x80) {
-	    return XK_Alt_R;
-	}
+        if (state & EXTENDED_MASK) {
+            return XK_Alt_R;
+        }
 	break;
     }
     return keymap[keycode];