diff --git a/src/calibre/gui2/__init__.py b/src/calibre/gui2/__init__.py
index f69788e849..0b21502327 100644
--- a/src/calibre/gui2/__init__.py
+++ b/src/calibre/gui2/__init__.py
@@ -248,10 +248,11 @@ def error_dialog(parent, title, msg, det_msg='', show=False,
         return d.exec_()
     return d
 
-def question_dialog(parent, title, msg, det_msg='', show_copy_button=False):
+def question_dialog(parent, title, msg, det_msg='', show_copy_button=False,
+        default_yes=True):
     from calibre.gui2.dialogs.message_box import MessageBox
     d = MessageBox(MessageBox.QUESTION, title, msg, det_msg, parent=parent,
-                    show_copy_button=show_copy_button)
+                    show_copy_button=show_copy_button, default_yes=default_yes)
     return d.exec_() == d.Accepted
 
 def info_dialog(parent, title, msg, det_msg='', show=False,
diff --git a/src/calibre/gui2/actions/choose_library.py b/src/calibre/gui2/actions/choose_library.py
index fb180176df..32460b6bec 100644
--- a/src/calibre/gui2/actions/choose_library.py
+++ b/src/calibre/gui2/actions/choose_library.py
@@ -252,11 +252,12 @@ class ChooseLibraryAction(InterfaceAction):
 
     def delete_requested(self, name, location):
         loc = location.replace('/', os.sep)
-        if not question_dialog(self.gui, _('Are you sure?'), '<p>'+
+        if not question_dialog(self.gui, _('Are you sure?'),
+                _('<h1 style="color:red">WARNING</h1>')+
                 _('<b style="color: red">All files</b> (not just ebooks) '
                     'from <br><br><b>%s</b><br><br> will be '
                 '<b>permanently deleted</b>. Are you sure?') % loc,
-                show_copy_button=False):
+                show_copy_button=False, default_yes=False):
             return
         exists = self.gui.library_view.model().db.exists_at(loc)
         if exists:
diff --git a/src/calibre/gui2/dialogs/message_box.py b/src/calibre/gui2/dialogs/message_box.py
index c9198c4aa2..7fd7a0addf 100644
--- a/src/calibre/gui2/dialogs/message_box.py
+++ b/src/calibre/gui2/dialogs/message_box.py
@@ -23,7 +23,7 @@ class MessageBox(QDialog, Ui_Dialog): # {{{
                  det_msg='',
                  q_icon=None,
                  show_copy_button=True,
-                 parent=None):
+                 parent=None, default_yes=True):
         QDialog.__init__(self, parent)
         if q_icon is None:
             icon = {
@@ -65,7 +65,9 @@ class MessageBox(QDialog, Ui_Dialog): # {{{
         self.is_question = type_ == self.QUESTION
         if self.is_question:
             self.bb.setStandardButtons(self.bb.Yes|self.bb.No)
-            self.bb.button(self.bb.Yes).setDefault(True)
+            self.bb.button(self.bb.Yes if default_yes else self.bb.No
+                    ).setDefault(True)
+            self.default_yes = default_yes
         else:
             self.bb.button(self.bb.Ok).setDefault(True)
 
@@ -101,7 +103,8 @@ class MessageBox(QDialog, Ui_Dialog): # {{{
         ret = QDialog.showEvent(self, ev)
         if self.is_question:
             try:
-                self.bb.button(self.bb.Yes).setFocus(Qt.OtherFocusReason)
+                self.bb.button(self.bb.Yes if self.default_yes else self.bb.No
+                        ).setFocus(Qt.OtherFocusReason)
             except:
                 pass# Buttons were changed
         else: