fix: window.getSelection() can return null on Firefox

1 files changed, 2 insertions, 1 deletions

diff --git a/ext/js/language/text-scanner.js b/ext/js/language/text-scanner.js
index 6fa7a454..af5cc8fe 100644
--- a/ext/js/language/text-scanner.js
+++ b/ext/js/language/text-scanner.js
@@ -145,7 +145,8 @@ class TextScanner extends EventDispatcher {
 
         if (value) {
             this._hookEvents();
-            this._userHasNotSelectedAnythingManually = window.getSelection().isCollapsed;
+            const selection = window.getSelection();
+            this._userHasNotSelectedAnythingManually = (selection === null) ? true : selection.isCollapsed;
         }
     }