diff --git a/editions/dev/tiddlers/new/WidgetSubclassingMechanism b/editions/dev/tiddlers/new/WidgetSubclassingMechanism.tid
similarity index 97%
rename from editions/dev/tiddlers/new/WidgetSubclassingMechanism
rename to editions/dev/tiddlers/new/WidgetSubclassingMechanism.tid
index 734d2a309..3f39d4e3a 100644
--- a/editions/dev/tiddlers/new/WidgetSubclassingMechanism
+++ b/editions/dev/tiddlers/new/WidgetSubclassingMechanism.tid
@@ -4,7 +4,7 @@ title: WidgetSubclassingMechanism
 
 !! Introduction
 
-The widget subclassing mechanism allows widgets to be subclassed with additional methods and properties. The subclassed widgets can either overwrite the existing definition of the baseclass widget, or it can be made availabel as a new widget
+The widget subclassing mechanism allows widgets to be subclassed with additional methods and properties. The subclassed widgets can either overwrite the existing definition of the baseclass widget, or it can be made available as a new widget
 
 Widget subclasses are defined in modules of module-type `widget-subclass`. They should export the following properties: