diff --git a/labelme/app.py b/labelme/app.py
index 43a61810ffbc9f57a6d6176cf62fbdf2a191f1e5..ba5a6db54325dfff29fdbd4c42d1bd04f3c05354 100644
--- a/labelme/app.py
+++ b/labelme/app.py
@@ -606,12 +606,12 @@ class MainWindow(QtWidgets.QMainWindow, WindowMixin):
             return
         item = item if item else self.currentItem()
         text = self.labelDialog.popUp(item.text())
+        if text is None:
+            return
         if not self.validateLabel(text):
             self.errorMessage('Invalid label',
                               "Invalid label '{}' with validation type '{}'"
                               .format(text, self._validate_label))
-            text = None
-        if text is None:
             return
         item.setText(text)
         self.setDirty()
@@ -747,7 +747,7 @@ class MainWindow(QtWidgets.QMainWindow, WindowMixin):
         if items:
             text = items[0].text()
         text = self.labelDialog.popUp(text)
-        if not self.validateLabel(text):
+        if text is not None and not self.validateLabel(text):
             self.errorMessage('Invalid label',
                               "Invalid label '{}' with validation type '{}'"
                               .format(text, self._validate_label))