Fix #2002753 [Error when ejecting while in Device Mode](https://bugs.launchpad.net/calibre/+bug/2002753)

src/calibre/gui2/library/models.py

@@ -1701,6 +1701,10 @@ class DeviceBooksModel(BooksModel):  # {{{
     def current_changed(self, current, previous, emit_signal=True):
         if current.isValid():
             idx = current.row()
+            try:
+                self.db[self.map[idx]]
+            except Exception:
+                return  # can happen if the device is ejected
             try:
                 data = self.get_book_display_info(idx)
             except Exception: