winex11.drv: Send missed KEYUP events on KeymapNotify.

dlls/winex11.drv/event.c

@@ -775,6 +775,8 @@ static BOOL X11DRV_FocusIn( HWND hwnd, XEvent *xev )
     if (is_virtual_desktop() && hwnd == NtUserGetDesktopWindow()) retry_grab_clipping_window();
     if (hwnd == NtUserGetDesktopWindow()) return FALSE;
 
+    x11drv_thread_data()->keymapnotify_hwnd = hwnd;
+
     /* when keyboard grab is released, re-apply the cursor clipping rect */
     was_grabbed = keyboard_grabbed;
     keyboard_grabbed = event->mode == NotifyGrab || event->mode == NotifyWhileGrabbed;

dlls/winex11.drv/keyboard.c

@@ -1192,11 +1192,19 @@ BOOL X11DRV_KeymapNotify( HWND hwnd, XEvent *event )
     int i, j;
     BYTE keystate[256];
     WORD vkey;
+    DWORD flags;
+    KeyCode keycode;
+    HWND keymapnotify_hwnd;
     BOOL changed = FALSE;
     struct {
         WORD vkey;
+        WORD scan;
         WORD pressed;
     } keys[256];
+    struct x11drv_thread_data *thread_data = x11drv_thread_data();
+
+    keymapnotify_hwnd = thread_data->keymapnotify_hwnd;
+    thread_data->keymapnotify_hwnd = NULL;
 
     if (!get_async_key_state( keystate )) return FALSE;
 
@@ -1211,11 +1219,17 @@ BOOL X11DRV_KeymapNotify( HWND hwnd, XEvent *event )
     {
         for (j = 0; j < 8; j++)
         {
-            vkey = keyc2vkey[(i * 8) + j];
+            keycode = (i * 8) + j;
+            vkey = keyc2vkey[keycode];
 
             /* If multiple keys map to the same vkey, we want to report it as
              * pressed iff any of them are pressed. */
-            if (!keys[vkey & 0xff].vkey) keys[vkey & 0xff].vkey = vkey;
+            if (!keys[vkey & 0xff].vkey)
+            {
+                keys[vkey & 0xff].vkey = vkey;
+                keys[vkey & 0xff].scan = keyc2scan[keycode] & 0xff;
+            }
+
             if (event->xkeymap.key_vector[i] & (1<<j)) keys[vkey & 0xff].pressed = TRUE;
         }
     }
@@ -1227,6 +1241,31 @@ BOOL X11DRV_KeymapNotify( HWND hwnd, XEvent *event )
             TRACE( "Adjusting state for vkey %#.2x. State before %#.2x\n",
                    keys[vkey].vkey, keystate[vkey]);
 
+            /* This KeymapNotify follows a FocusIn(mode=NotifyUngrab) event,
+             * which is caused by a keyboard grab being released.
+             * See XGrabKeyboard().
+             *
+             * We might have missed some key press/release events while the
+             * keyboard was grabbed, but keyboard grab doesn't generate focus
+             * lost / focus gained events on the Windows side, so the affected
+             * program is not aware that it needs to resync the keyboard state.
+             *
+             * This, for example, may cause Alt being stuck after using Alt+Tab.
+             *
+             * To work around that problem we sync any possible key releases.
+             *
+             * Syncing key presses is not feasible as window managers differ in
+             * event sequences, e.g. KDE performs two keyboard grabs for
+             * Alt+Tab, which would sync the Tab press.
+             */
+            if (keymapnotify_hwnd && !keys[vkey].pressed)
+            {
+                TRACE( "Sending KEYUP for a modifier %#.2x\n", vkey);
+                flags = KEYEVENTF_KEYUP;
+                if (keys[vkey].vkey & 0x1000) flags |= KEYEVENTF_EXTENDEDKEY;
+                X11DRV_send_keyboard_input( keymapnotify_hwnd, vkey, keys[vkey].scan, flags, NtGetTickCount() );
+            }
+
             update_key_state( keystate, vkey, keys[vkey].pressed );
             changed = TRUE;
         }

dlls/winex11.drv/mouse.c

@@ -1611,6 +1611,8 @@ BOOL X11DRV_EnterNotify( HWND hwnd, XEvent *xev )
 
     TRACE( "hwnd %p/%lx pos %d,%d detail %d\n", hwnd, event->window, event->x, event->y, event->detail );
 
+    x11drv_thread_data()->keymapnotify_hwnd = hwnd;
+
     if (hwnd == x11drv_thread_data()->grab_hwnd) return FALSE;
 
     /* simulate a mouse motion event */

dlls/winex11.drv/x11drv.h

@@ -382,6 +382,7 @@ struct x11drv_thread_data
     XEvent  *current_event;        /* event currently being processed */
     HWND     grab_hwnd;            /* window that currently grabs the mouse */
     HWND     last_focus;           /* last window that had focus */
+    HWND     keymapnotify_hwnd;    /* window that should receive modifier release events */
     XIM      xim;                  /* input method */
     HWND     last_xic_hwnd;        /* last xic window */
     XFontSet font_set;             /* international text drawing font set */