show # of decks using options group

aqt/deckconf.py

@@ -79,6 +79,13 @@ class DeckConf(QDialog):
         conf = self.confList[idx]
         self.deck['conf'] = conf['id']
         self.loadConf()
+        cnt = 0
+        for d in self.mw.col.decks.all():
+            if d['dyn']:
+                continue
+            if d['conf'] == conf['id']:
+                cnt += 1
+        self.form.count.setText(_("%d decks use this options group") % cnt)
 
     def addGroup(self):
         name = getOnlyText(_("New options group name:"))

designer/dconf.ui

@@ -55,6 +55,16 @@
      </item>
     </layout>
    </item>
+   <item>
+    <widget class="QLabel" name="count">
+     <property name="text">
+      <string>TextLabel</string>
+     </property>
+     <property name="alignment">
+      <set>Qt::AlignCenter</set>
+     </property>
+    </widget>
+   </item>
    <item>
     <widget class="QTabWidget" name="tabWidget">
      <property name="currentIndex">