--- a/im/modules/ibCore.jsm
+++ b/im/modules/ibCore.jsm
@@ -269,18 +269,21 @@ var Core = {
     promptMessage = PluralForm.get(unreadConvsCount, promptMessage)
                               .replace("#1", unreadConvsCount);
 
     let prompts = Services.prompt;
     let flags = prompts.BUTTON_TITLE_IS_STRING * prompts.BUTTON_POS_0 +
                 prompts.BUTTON_TITLE_CANCEL * prompts.BUTTON_POS_1 +
                 prompts.BUTTON_POS_1_DEFAULT;
     let checkbox = {value: false};
-    let convWindow = Services.wm.getMostRecentWindow("Messenger:convs");
-    if (prompts.confirmEx(convWindow, promptTitle, promptMessage, flags,
+    let parentWindow = Services.wm.getMostRecentWindow("Messenger:convs") ||
+                       Services.wm.getMostRecentWindow("Messenger:blist");
+    if (parentWindow)
+      parentWindow.focus();
+    if (prompts.confirmEx(parentWindow, promptTitle, promptMessage, flags,
                           button, null, null, promptCheckbox, checkbox)) {
       aCancelQuit.data = true;
       return;
     }
 
     if (checkbox.value)
       Services.prefs.setBoolPref("messenger.warnOnQuit", false);
   },