diff --git a/src/calibre/gui2/preferences/main.py b/src/calibre/gui2/preferences/main.py
index 6653fe2b67..c82ddcc022 100644
--- a/src/calibre/gui2/preferences/main.py
+++ b/src/calibre/gui2/preferences/main.py
@@ -101,9 +101,9 @@ class Category(QWidget): # {{{
             ac.setStatusTip(p.description)
             self.actions.append(ac)
             w = self.bar.widgetForAction(ac)
-            w.setStyleSheet('QToolButton { margin-right: 20px; min-width: 100px }')
             w.setCursor(Qt.PointingHandCursor)
             w.setAutoRaise(True)
+            w.setMinimumWidth(100)
 
     def triggered(self, plugin, *args):
         self.plugin_activated.emit(plugin)