diff --git a/tools/lazdatadesktop/frmmain.lfm b/tools/lazdatadesktop/frmmain.lfm
index 01fa8eb593..03acf6dced 100644
--- a/tools/lazdatadesktop/frmmain.lfm
+++ b/tools/lazdatadesktop/frmmain.lfm
@@ -1693,7 +1693,7 @@ object MainForm: TMainForm
     }
   end
   object ODDD: TOpenDialog
-    DefaultExt = '.fpd'
+    DefaultExt = '.fdd'
     FilterIndex = 0
     Options = [ofReadOnly, ofFileMustExist, ofEnableSizing, ofViewDetail]
     left = 104
@@ -1707,7 +1707,7 @@ object MainForm: TMainForm
     top = 136
   end
   object SDDD: TSaveDialog
-    DefaultExt = '.fpd'
+    DefaultExt = '.fdd'
     FilterIndex = 0
     left = 160
     top = 80
diff --git a/tools/lazdatadesktop/lazdatadeskstr.pas b/tools/lazdatadesktop/lazdatadeskstr.pas
index c0757eb6b6..22dafc6af1 100644
--- a/tools/lazdatadesktop/lazdatadeskstr.pas
+++ b/tools/lazdatadesktop/lazdatadeskstr.pas
@@ -267,9 +267,9 @@ resourcestring
   sld_Connectionlv4        = 'Description';
   //
   sld_opendatadictionarytitle      = 'Open data dictionary';
-  sld_opendatadictionaryfilter     = 'Data dictionary files|*.fpd|Ini files|*.ini|All files|*.*';
+  sld_opendatadictionaryfilter     = 'Data dictionary files (fdd)|*.fdd|Ini files|*.ini|All files|*.*';
   sld_savefileastitle              = 'Save file as';
-  sld_savefileasfilter             = 'Data dictionary files|*.fpd|Ini files|*.ini|All files|*.*';
+  sld_savefileasfilter             = 'Data dictionary files (fdd)|*.fdd|Ini files|*.ini|All files|*.*';
   //
   sld_Fromconnection       = 'From connection';
   //