diff --git a/src/preferences/keymap/Keymap.cpp b/src/preferences/keymap/Keymap.cpp
index da146a9f54..b30bb8e61f 100644
--- a/src/preferences/keymap/Keymap.cpp
+++ b/src/preferences/keymap/Keymap.cpp
@@ -154,6 +154,14 @@ Keymap::Save(entry_ref &ref)
 }
 
 
+bool Keymap::Equals(const Keymap& map) const
+{
+	// not really efficient but this is the only way i found
+	// to reliably compare keymaps (used only for apply and revert)
+	return memcmp( &map.fKeys, &fKeys, sizeof(key_map)) == 0;
+}
+
+
 /* we need to know if a key is a modifier key to choose 
 	a valid key when several are pressed together
 */
diff --git a/src/preferences/keymap/Keymap.h b/src/preferences/keymap/Keymap.h
index 1b98c1990e..a3bd0ca19c 100644
--- a/src/preferences/keymap/Keymap.h
+++ b/src/preferences/keymap/Keymap.h
@@ -23,6 +23,8 @@ public:
 	bool IsDeadSecondKey(uint32 keyCode, uint32 modifiers, uint8 activeDeadKey);
 	void GetChars(uint32 keyCode, uint32 modifiers, uint8 activeDeadKey, char** chars, int32* numBytes);
 	status_t Use();
+	bool Equals(const Keymap& map) const;
+	
 private:
 	char *fChars;
 	key_map fKeys;
diff --git a/src/preferences/keymap/KeymapWindow.cpp b/src/preferences/keymap/KeymapWindow.cpp
index 8df65fcbb5..862853c0f3 100644
--- a/src/preferences/keymap/KeymapWindow.cpp
+++ b/src/preferences/keymap/KeymapWindow.cpp
@@ -50,6 +50,8 @@ KeymapWindow::KeymapWindow()
 	:	BWindow(BRect(80, 25, 692, 281), "Keymap", B_TITLED_WINDOW,
 			B_NOT_ZOOMABLE | B_NOT_RESIZABLE | B_ASYNCHRONOUS_CONTROLS )
 {
+	fFirstTime = true;
+	
 	// Add the menu bar
 	BMenuBar *menubar = AddMenuBar();
 
@@ -81,6 +83,7 @@ KeymapWindow::KeymapWindow()
 	fRevertButton = new BButton(BRect(442, 200, 515, 220), "revertButton",
 		 "Revert", new BMessage(kMsgRevertKeymap));
 	placeholderView->AddChild(fRevertButton);
+	UpdateButtons();
 	
 	BPath path;
 	find_directory(B_USER_SETTINGS_DIRECTORY, &path);
@@ -216,7 +219,6 @@ KeymapWindow::AddMaps(BView *placeholderView)
 	fUserListView->SetSelectionMessage(new BMessage(kMsgUserMapSelected));
 	
 	FillSystemMaps();
-	
 	FillUserMaps();
 }
 
@@ -299,6 +301,7 @@ KeymapWindow::MessageReceived(BMessage* message)
 				
 				// Deselect item in other BListView
 				fUserListView->DeselectAll();
+				UpdateButtons();
 			}
 		}
 			break;
@@ -308,17 +311,28 @@ KeymapWindow::MessageReceived(BMessage* message)
 				static_cast<KeymapListItem*>(fUserListView->ItemAt(fUserListView->CurrentSelection()));
 			if (keymapListItem) {
 				fCurrentMap.Load(keymapListItem->KeymapEntry());
+				
+				if (fFirstTime) {
+					fPreviousMap.Load(keymapListItem->KeymapEntry());
+					fAppliedMap.Load(keymapListItem->KeymapEntry());
+					fFirstTime = false;
+				}
+				
 				fMapView->Invalidate();
 				
 				// Deselect item in other BListView
 				fSystemListView->DeselectAll();
+				UpdateButtons();
 			}
 		}
 			break;
 		case kMsgUseKeymap:
 			UseKeymap();
+			UpdateButtons();
 			break;
-		case kMsgRevertKeymap:	// do nothing, just like the original
+		case kMsgRevertKeymap:
+			RevertKeymap();
+			UpdateButtons();
 			break;
 		default:
 			BWindow::MessageReceived(message);
@@ -327,6 +341,43 @@ KeymapWindow::MessageReceived(BMessage* message)
 }
 
 
+ void 
+KeymapWindow::UpdateButtons()
+{
+	fUseButton->SetEnabled(!fCurrentMap.Equals(fAppliedMap));
+	fRevertButton->SetEnabled(!fCurrentMap.Equals(fPreviousMap));
+}
+
+
+void 
+KeymapWindow::RevertKeymap()
+{
+	//saves previous map to the Key_map file
+	
+	printf("REVERT\n");
+	BPath path;
+	if (find_directory(B_USER_SETTINGS_DIRECTORY, &path)!=B_OK)
+		return;
+	
+	path.Append("Key_map");
+
+	entry_ref ref;
+	get_ref_for_path(path.Path(), &ref);
+
+	status_t err;
+	if ((err = fPreviousMap.Save(ref)) != B_OK) {
+		printf("error when saving : %s", strerror(err));
+		return;
+	}
+	fPreviousMap.Use();
+	fAppliedMap.Load(ref);
+	
+	//select and load it (first item in fUserListView is a ref to Key_map)
+	fUserListView->DeselectAll();
+	fUserListView->Select(0);		
+}
+
+
 void 
 KeymapWindow::UseKeymap()
 {
@@ -345,6 +396,7 @@ KeymapWindow::UseKeymap()
 		return;
 	}
 	fCurrentMap.Use();
+	fAppliedMap.Load(ref);
 	
 	fUserListView->Select(0);
 }
@@ -407,13 +459,6 @@ KeymapWindow::FillUserMaps()
 }
 
 
-BEntry* 
-KeymapWindow::CurrentMap()
-{
-	return NULL;
-}
-
-
 MapView::MapView(BRect rect, const char *name, Keymap* keymap)
 	: BControl(rect, name, NULL, NULL, B_FOLLOW_LEFT | B_FOLLOW_TOP, B_WILL_DRAW),
 		fCurrentFont(*be_plain_font),
diff --git a/src/preferences/keymap/KeymapWindow.h b/src/preferences/keymap/KeymapWindow.h
index d965889e28..c1c8659c5c 100644
--- a/src/preferences/keymap/KeymapWindow.h
+++ b/src/preferences/keymap/KeymapWindow.h
@@ -74,6 +74,16 @@ public:
 	void	MessageReceived( BMessage* message );
 
 protected:
+	BMenuBar			*AddMenuBar();
+	void				AddMaps(BView *placeholderView);
+	void				UseKeymap();
+	void				RevertKeymap();
+	void				UpdateButtons();
+	
+	void 				FillSystemMaps();
+	void 				FillUserMaps();
+		
+
 	BListView			*fSystemListView;
 	BListView			*fUserListView;
 	// the map that's currently highlighted
@@ -82,18 +92,12 @@ protected:
 	BMenu				*fFontMenu;
 	
 	MapView				*fMapView;
-
-	BMenuBar			*AddMenuBar();
-	void				AddMaps(BView *placeholderView);
-	void				UseKeymap();
-	
-	void 				FillSystemMaps();
-	void 				FillUserMaps();
-	
-	BEntry* 			CurrentMap();
 		
 	Keymap				fCurrentMap;
-	
+	Keymap				fPreviousMap;
+	Keymap				fAppliedMap;
+	bool				fFirstTime;
+			
 	BFilePanel 			*fOpenPanel;		// the file panel to open
 	BFilePanel 			*fSavePanel;		// the file panel to save
 };