From d24d485f064d89a200fab3e9e1c15c4b420c946d Mon Sep 17 00:00:00 2001
From: Damien Elmes <gpg@ankiweb.net>
Date: Mon, 15 Apr 2019 12:20:12 +1000
Subject: [PATCH] preview code shouldn't assume self.card is valid

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

diff --git a/aqt/browser.py b/aqt/browser.py
index a4931bd3f..375676161 100644
--- a/aqt/browser.py
+++ b/aqt/browser.py
@@ -1388,6 +1388,7 @@ where id in %s""" % ids2str(sf))
         if not c or not self.singleCard:
             txt = _("(please select 1 card)")
             bodyclass = ""
+            self._lastPreviewState = None
         else:
             if self._previewBothSides:
                 self._previewState = "answer"
@@ -1425,7 +1426,7 @@ where id in %s""" % ids2str(sf))
             txt = mungeQA(self.col, txt)
             txt = runFilter("prepareQA", txt, c,
                             "preview"+self._previewState.capitalize())
-        self._lastPreviewState = self._previewStateAndMod()
+            self._lastPreviewState = self._previewStateAndMod()
         self._updatePreviewButtons()
         self._previewWeb.eval(
             "{}({},'{}');".format(func, json.dumps(txt), bodyclass))