diff --git a/khal/ui/__init__.py b/khal/ui/__init__.py
index f3ea06de0..ab78d5cdf 100644
--- a/khal/ui/__init__.py
+++ b/khal/ui/__init__.py
@@ -754,7 +754,7 @@ def update_colors(new_start: dt.date, new_end: dt.date, everything: bool=False):
         assert not self.editor
         if external_edit:
             self.pane.window.loop.stop()
-            ics = click.edit(event.raw)
+            ics = click.edit(event.raw, extension=".ics")
             self.pane.window.loop.start()
             if ics is None:
                 return