diff --git a/ModuleFixTarget.py b/ModuleFixTarget.py
index edb9b49..b3f625f 100644
--- a/ModuleFixTarget.py
+++ b/ModuleFixTarget.py
@@ -375,9 +375,9 @@ class WndFixTarget(QWidget):
     #df.to_csv(filename, float_format="%.6f")
     #import numpy as np
     base,ext=os.path.splitext(filename)
-    if not ext.lower():
-      ext='json'
-      filename=base+'.'+ext
+    if ext=='':
+        ext='.json'
+        filename=base+ext
     try:
       wnd=app._mainWnd
     except AttributeError:
@@ -387,7 +387,7 @@ class WndFixTarget(QWidget):
       grp=wnd._goTracked
       data=grp.childItems()
 
-    if ext.lower()=='json':
+    if ext.lower()=='.json':
       with open(filename, 'w') as f:
         json.dump(data, f,cls=MyJsonEncoder, indent=2)#separators=(',', ':')
     else: