diff --git a/src/ui/highlighter.cpp b/src/ui/highlighter.cpp
--- a/src/ui/highlighter.cpp
+++ b/src/ui/highlighter.cpp
@@ -194,6 +194,9 @@
         } else {
             cursor = d->plainTextEdit->textCursor();
         }
+        if (cursor.hasSelection()) {
+            cursor.clearSelection();
+        }
         cursor.insertText(QString());
     }
     //if (d->checksDone == d->checksRequested)