diff --git a/src/FbTk/EventManager.cc b/src/FbTk/EventManager.cc
index ae52908f..b9d5e987 100644
--- a/src/FbTk/EventManager.cc
+++ b/src/FbTk/EventManager.cc
@@ -179,9 +179,7 @@ void EventManager::dispatch(Window win, XEvent &ev, bool parent) {
         evhand->exposeEvent(ev.xexpose);
     break;
     case EnterNotify:
-        if (ev.xcrossing.mode != NotifyGrab &&
-            ev.xcrossing.mode != NotifyUngrab)
-            evhand->enterNotifyEvent(ev.xcrossing);
+        evhand->enterNotifyEvent(ev.xcrossing);
     break;
     case LeaveNotify:
         if (ev.xcrossing.mode != NotifyGrab &&
diff --git a/src/Window.cc b/src/Window.cc
index 3c32d0e4..4e2aed17 100644
--- a/src/Window.cc
+++ b/src/Window.cc
@@ -2716,12 +2716,21 @@ void FluxboxWindow::motionNotifyEvent(XMotionEvent &me) {
 
 void FluxboxWindow::enterNotifyEvent(XCrossingEvent &ev) {
 
-    // ignore grab activates, or if we're not visible
-    if (ev.mode == NotifyGrab || ev.mode == NotifyUngrab ||
-        !isVisible()) {
+    static FluxboxWindow *s_last_really_entered = 0;
+
+    if (ev.mode == NotifyUngrab && s_last_really_entered == this) {
+        // if this results from an ungrab, only act if the window really changed.
+        // otherwise we might pollute the focus which could have been assigned
+        // by alt+tab (bug #597)
         return;
     }
 
+    // ignore grab activates, or if we're not visible
+    if (ev.mode == NotifyGrab || !isVisible()) {
+        return;
+    }
+
+    s_last_really_entered = this;
     if (ev.window == frame().window())
         Fluxbox::instance()->keys()->doAction(ev.type, ev.state, 0,
                                               Keys::ON_WINDOW, m_client);