From 604ae4c33a8236c582ebe7ecd09c09f64d6a0a3b Mon Sep 17 00:00:00 2001
From: mrmr1993
Date: Thu, 2 Nov 2017 13:52:03 +0000
Subject: FF: Don't use Selection.getRangeAt(0) when there are no ranges

This fixes #2757.
---
 content_scripts/mode_find.coffee | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/content_scripts/mode_find.coffee b/content_scripts/mode_find.coffee
index 0fc147a3..950b08e9 100644
--- a/content_scripts/mode_find.coffee
+++ b/content_scripts/mode_find.coffee
@@ -82,6 +82,7 @@ class FindMode extends Mode
     FindMode.handleEscape() if event
 
   restoreSelection: ->
+    return unless @initialRange
     range = @initialRange
     selection = getSelection()
     selection.removeAllRanges()
@@ -241,7 +242,10 @@ getCurrentRange = ->
     range
   else
     selection.collapseToStart() if selection.type == "Range"
-    selection.getRangeAt 0
+    if selection.rangeCount > 0
+      selection.getRangeAt 0
+    else # Firefox returns a selection with no ranges and null anchor/focusNode in some situations.
+      null
 
 getLinkFromSelection = ->
   node = window.getSelection().anchorNode
-- 
cgit v1.2.3