diff --git a/src/calibre/gui2/device.py b/src/calibre/gui2/device.py
index ab98470a22..855d05ff58 100644
--- a/src/calibre/gui2/device.py
+++ b/src/calibre/gui2/device.py
@@ -1013,29 +1013,29 @@ class DeviceGUI(object):
                 break
         return loc
 
-    def set_books_in_library(self, booklist):
-        '''
-        Set the 'in_library' attribute for all books on a device to True if a
-        book on the device is in the library, else False
-        '''
-        # First build a cache of the library, so the search isn't On**2
-        cache = {}
+    def set_books_in_library(self, booklist, reset = False):
+        if reset:
+            self.book_in_library_cache = None
+            return
+
+        # First build a self.book_in_library_cache of the library, so the search isn't On**2
+        self.book_in_library_cache = {}
         for id, title in self.library_view.model().db.all_titles():
             title = re.sub('(?u)\W|[_]', '', title.lower())
-            if title not in cache:
-                cache[title] = {'authors':set(), 'db_ids':set()}
+            if title not in self.book_in_library_cache:
+                self.book_in_library_cache[title] = {'authors':set(), 'db_ids':set()}
             au = self.library_view.model().db.authors(id, index_is_id=True)
             authors = au.lower() if au else ''
             authors = re.sub('(?u)\W|[_]', '', authors)
-            cache[title]['authors'].add(authors)
-            cache[title]['db_ids'].add(id)
+            self.book_in_library_cache[title]['authors'].add(authors)
+            self.book_in_library_cache[title]['db_ids'].add(id)
 
         # Now iterate through all the books on the device, setting the in_library field
         for book in booklist:
             book_title = book.title.lower() if book.title else ''
             book_title = re.sub('(?u)\W|[_]', '', book_title)
             book.in_library = False
-            d = cache.get(book_title, None)
+            d = self.book_in_library_cache.get(book_title, None)
             if d is not None:
                 if book.db_id in d['db_ids']:
                     book.in_library = True
diff --git a/src/calibre/gui2/library.py b/src/calibre/gui2/library.py
index 5d4686b4d2..90dc3eb1ea 100644
--- a/src/calibre/gui2/library.py
+++ b/src/calibre/gui2/library.py
@@ -1266,13 +1266,6 @@ class DeviceBooksModel(BooksModel):
         self.search_engine = OnDeviceSearch(self)
         self.editable = True
         self.book_in_library = None
-        self.loc = None
-
-    def set_book_in_library_func(self, func, loc):
-        self.book_in_library = func
-        self.loc = loc
-        # Not convinced that this should be here ...
-        func(self.db)
 
     def mark_for_deletion(self, job, rows):
         self.marked_for_deletion[job] = self.indices(rows)
diff --git a/src/calibre/gui2/ui.py b/src/calibre/gui2/ui.py
index df7c246e76..4f5e71174c 100644
--- a/src/calibre/gui2/ui.py
+++ b/src/calibre/gui2/ui.py
@@ -992,15 +992,16 @@ class Main(MainWindow, Ui_MainWindow, DeviceGUI):
             else:
                 self.device_job_exception(job)
             return
+        self.set_books_in_library(None, reset=True)
         mainlist, cardalist, cardblist = job.result
         self.memory_view.set_database(mainlist)
-        self.memory_view.model().set_book_in_library_func(self.set_books_in_library, 'main')
+        self.set_books_in_library(mainlist)
         self.memory_view.set_editable(self.device_manager.device.CAN_SET_METADATA)
         self.card_a_view.set_database(cardalist)
-        self.card_a_view.model().set_book_in_library_func(self.set_books_in_library, 'carda')
+        self.set_books_in_library(cardalist)
         self.card_a_view.set_editable(self.device_manager.device.CAN_SET_METADATA)
         self.card_b_view.set_database(cardblist)
-        self.card_b_view.model().set_book_in_library_func(self.set_books_in_library, 'cardb')
+        self.set_books_in_library(cardblist)
         self.card_b_view.set_editable(self.device_manager.device.CAN_SET_METADATA)
         for view in (self.memory_view, self.card_a_view, self.card_b_view):
             view.sortByColumn(3, Qt.DescendingOrder)