layout: add new_window_takes_over_fullscreen mode 2

fixes #3486

src/events/Windows.cpp

@@ -471,6 +471,8 @@ void Events::listener_mapWindow(void* owner, void* data) {
     if (PWORKSPACE->m_bHasFullscreenWindow && !requestsFullscreen) {
         if (*PNEWTAKESOVERFS == 0)
             PWINDOW->m_bNoInitialFocus = true;
+        else if (*PNEWTAKESOVERFS == 2)
+            g_pCompositor->setWindowFullscreen(g_pCompositor->getFullscreenWindowOnWorkspace(PWORKSPACE->m_iID), false, FULLSCREEN_INVALID);
         else
             requestsFullscreen = true;
     }