fixed handling of ISO_Left_Tab when that is not mapped to a

keycode by mapping it to tab with shift pressed.

client/CXWindowsSecondaryScreen.cpp

@@ -6,6 +6,7 @@
 #include <X11/X.h>
 #include <X11/Xutil.h>
 #define XK_MISCELLANY
+#define XK_XKB_KEYS
 #include <X11/keysymdef.h>
 #include <X11/extensions/XTest.h>
 
@@ -664,6 +665,10 @@ bool					CXWindowsSecondaryScreen::findKeyCode(
 			id = XK_Delete;
 			break;
 
+		case XK_ISO_Left_Tab:
+			id = XK_Tab;
+			break;
+
 		default:
 			return false;
 		}