diff --git a/src/apps/diskusage/App.cpp b/src/apps/diskusage/App.cpp
index 5e5b03b046..7133038344 100644
--- a/src/apps/diskusage/App.cpp
+++ b/src/apps/diskusage/App.cpp
@@ -22,7 +22,8 @@
 App::App()
 	: BApplication(kAppSignature),
 	  fResources(read_resources(kAppSignature)),
-	  fMainWindow(NULL)
+	  fMainWindow(NULL),
+	  fSavedRefsReceived(NULL)
 {
 }
 
@@ -30,6 +31,7 @@ App::App()
 App::~App()
 {
 	delete fResources;
+	delete fSavedRefsReceived;
 }
 
 
@@ -51,7 +53,13 @@ App::ArgvReceived(int32 argc, char** argv)
 void
 App::RefsReceived(BMessage* message)
 {
-	fMainWindow->PostMessage(message);
+	if (fMainWindow == NULL) {
+		// ReadyToRun() has not been called yet, this happens when someone
+		// launches us with a B_REFS_RECEIVED message.
+		delete fSavedRefsReceived;
+		fSavedRefsReceived = new BMessage(*message);
+	} else
+		fMainWindow->PostMessage(message);
 }
 
 
@@ -74,6 +82,13 @@ App::ReadyToRun()
 	}
 
 	fMainWindow = new MainWindow(frame);
+
+	if (fSavedRefsReceived) {
+		// RefsReceived() was called earlier than ReadyToRun()
+		fMainWindow->PostMessage(fSavedRefsReceived);
+		delete fSavedRefsReceived;
+		fSavedRefsReceived = NULL;
+	}
 }
 
 
@@ -87,23 +102,11 @@ App::QuitRequested()
 	if (settings.AddRect("window frame", fMainWindow->Frame()) != B_OK
 		|| find_directory(B_USER_SETTINGS_DIRECTORY, &path) != B_OK
 		|| path.Append("DiskUsage") != B_OK
-		|| settingsFile.SetTo(path.Path(), B_WRITE_ONLY) != B_OK
+		|| settingsFile.SetTo(path.Path(),
+			B_CREATE_FILE | B_WRITE_ONLY | B_ERASE_FILE) != B_OK
 		|| settings.Flatten(&settingsFile) != B_OK) {
 		fprintf(stderr, "Failed to write application settings.\n");
 	}
 
 	return BApplication::QuitRequested();
 }
-
-
-// #pragma mark -
-
-
-int
-main()
-{
-	App app;
-	app.Run();
-	return 0;
-}
-
diff --git a/src/apps/diskusage/App.h b/src/apps/diskusage/App.h
index fe39ac2179..8965e0b2c4 100644
--- a/src/apps/diskusage/App.h
+++ b/src/apps/diskusage/App.h
@@ -28,6 +28,7 @@ public:
 private:
 			BResources*			fResources;
 			MainWindow*			fMainWindow;
+			BMessage*			fSavedRefsReceived;
 };
 
 #endif // APP_H
diff --git a/src/apps/diskusage/DiskUsage.cpp b/src/apps/diskusage/DiskUsage.cpp
new file mode 100644
index 0000000000..4cb23884b2
--- /dev/null
+++ b/src/apps/diskusage/DiskUsage.cpp
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 1998-2007 Matthijs Hollemans
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a 
+ * copy of this software and associated documentation files (the "Software"), 
+ * to deal in the Software without restriction, including without limitation 
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
+ * and/or sell copies of the Software, and to permit persons to whom the 
+ * Software is furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in 
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+// NOTE: This code is the same in TextSearch. Maybe it could be made
+// into some kind of common base class?
+
+#include "App.h"
+
+#include <AppFileInfo.h>
+#include <Entry.h>
+#include <Roster.h>
+#include <TrackerAddOn.h>
+
+#include "Common.h"
+
+
+int
+main() 
+{
+	App app;
+	app.Run();
+	return 0;
+}
+
+
+void
+process_refs(entry_ref dirRef, BMessage* message, void* /*reserved*/)
+{
+	// Tracker calls this function when the user invokes the add-on. 
+	// "dir_ref" contains the entry_ref of the current directory. 
+	// "message" is a standard B_REFS_RECEIVED BMessage whose "refs" 
+	// array contains the entry_refs of the selected files. The last
+	// argument, "reserved", is currently unused.
+	
+	// This version of TrackerGrep is a Tracker add-on, but primarily
+	// it is a stand-alone application. The add-on launches the app
+	// on the set of files you had selected in Tracker. That way you
+	// get the benefits of the Tracker add-on with the benefits of the
+	// stand-alone application.
+
+	if (!message->HasRef("refs"))
+		message->AddRef("refs", &dirRef);
+
+	// get the path of the Tracker add-on
+	image_info image;
+	int32 cookie = 0;
+	status_t status = get_next_image_info(0, &cookie, &image);
+
+	while (status == B_OK) {
+		if (((char*)process_refs >= (char*)image.text
+				&& (char*)process_refs <= (char*)image.text + image.text_size)
+			|| ((char*)process_refs >= (char*)image.data
+				&& (char*)process_refs <= (char*)image.data + image.data_size))
+			break;
+		
+		status = get_next_image_info(0, &cookie, &image);
+	}
+
+	entry_ref addonRef;
+
+	if (get_ref_for_path(image.name, &addonRef) == B_OK) {
+		// It's better to launch the application by its entry
+		// than by its application signature. There may be 
+		// multiple instances and we would not be certain
+		// that the desired one is launched - the one which was
+		// loaded into Tracker and whose process_refs() was called.
+		be_roster->Launch(&addonRef, message);
+	} else
+		be_roster->Launch(kAppSignature, message);
+}
diff --git a/src/apps/diskusage/Jamfile b/src/apps/diskusage/Jamfile
index 11132a97df..985c825db5 100644
--- a/src/apps/diskusage/Jamfile
+++ b/src/apps/diskusage/Jamfile
@@ -4,6 +4,7 @@ Application DiskUsage :
 	App.cpp
 	Common.cpp
 	ControlsView.cpp
+	DiskUsage.cpp
 	InfoWindow.cpp
 	MainWindow.cpp
 	PieView.cpp