From 6431f0b6b1bd483d4cc1cca2e06dd46c622dccbc Mon Sep 17 00:00:00 2001
From: Henrik Giesel <hengiesel@gmail.com>
Date: Sun, 10 Jan 2021 01:21:52 +0100
Subject: [PATCH] Prevent error when browser is closed with previewer open

---
 qt/aqt/browser.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/qt/aqt/browser.py b/qt/aqt/browser.py
index 7ea3393be..0fc9530fc 100644
--- a/qt/aqt/browser.py
+++ b/qt/aqt/browser.py
@@ -1577,7 +1577,8 @@ where id in %s"""
             self._previewer.close()
 
     def _on_preview_closed(self):
-        self.editor.web.eval("$('#previewButton').removeClass('highlighted')")
+        if self.editor.web:
+            self.editor.web.eval("$('#previewButton').removeClass('highlighted')")
         self._previewer = None
 
     # Card deletion