diff --git a/data/pref.xml b/data/pref.xml
index c09c5230c..84562f68d 100644
--- a/data/pref.xml
+++ b/data/pref.xml
@@ -278,6 +278,7 @@
       <option id="resize_scale" type="double" default="1" />
     </section>
     <section id="sprite_sheet">
+      <option id="defined" type="bool" default="false" />
       <option id="type" type="app::SpriteSheetType" default="app::SpriteSheetType::None" />
       <option id="columns" type="int" default="0" />
       <option id="rows" type="int" default="0" />
diff --git a/src/app/commands/cmd_export_sprite_sheet.cpp b/src/app/commands/cmd_export_sprite_sheet.cpp
index 1dbfcef08..fc19ac39a 100644
--- a/src/app/commands/cmd_export_sprite_sheet.cpp
+++ b/src/app/commands/cmd_export_sprite_sheet.cpp
@@ -757,6 +757,7 @@ void ExportSpriteSheetCommand::onExecute(Context* context)
     if (!window.ok())
       return;
 
+    docPref.spriteSheet.defined(true);
     docPref.spriteSheet.type(window.spriteSheetTypeValue());
     docPref.spriteSheet.columns(window.columnsValue());
     docPref.spriteSheet.rows(window.rowsValue());
@@ -778,6 +779,7 @@ void ExportSpriteSheetCommand::onExecute(Context* context)
     // Default preferences for future sprites
     DocumentPreferences& defPref(Preferences::instance().document(nullptr));
     defPref.spriteSheet = docPref.spriteSheet;
+    defPref.spriteSheet.defined(false);
     if (!defPref.spriteSheet.textureFilename().empty())
       defPref.spriteSheet.textureFilename.setValueAndDefault(kSpecifiedFilename);
     if (!defPref.spriteSheet.dataFilename().empty())
diff --git a/src/app/commands/cmd_repeat_last_export.cpp b/src/app/commands/cmd_repeat_last_export.cpp
index ab80da20a..b59d498b9 100644
--- a/src/app/commands/cmd_repeat_last_export.cpp
+++ b/src/app/commands/cmd_repeat_last_export.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2001-2015  David Capello
+// Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -51,8 +51,7 @@ void RepeatLastExportCommand::onExecute(Context* context)
     DocumentPreferences& docPref =
       Preferences::instance().document(document);
 
-    params.set("ui",
-      (docPref.spriteSheet.type() == app::SpriteSheetType::None ? "1": "0"));
+    params.set("ui", (docPref.spriteSheet.defined() ? "0": "1"));
   }
 
   context->executeCommand(cmd, params);