diff --git a/libgui/GuiCanvasWxBackend.py b/libgui/GuiCanvasWxBackend.py
index f3d4748..658c753 100644
--- a/libgui/GuiCanvasWxBackend.py
+++ b/libgui/GuiCanvasWxBackend.py
@@ -22,11 +22,8 @@ class GuiBufferedDC(wx.MemoryDC):
         viewRect = [m * n for m, n in zip(backend.cellSize, viewRect)]
         viewSize = [min(m, n) for m, n in zip(canvasSize, clientSize)]
         viewSize = [m * n for m, n in zip(backend.cellSize, viewSize)]
-        bitmap = wx.Bitmap(viewSize); self.SelectObject(bitmap);
-        bufferDc = wx.MemoryDC(); bufferDc.SelectObject(buffer);
-        self.Blit(0, 0, *viewSize, bufferDc, *viewRect)
-        bufferDc.SelectObject(wx.NullBitmap)
-        self.dc, self.viewSize = dc, viewSize
+        self.SelectObject(buffer); self.SetDeviceOrigin(*viewRect);
+        self.dc, self.viewRect, self.viewSize = dc, viewRect, viewSize
     # }}}
 
 class GuiCanvasWxBackend():
diff --git a/libroar/RoarCanvasWindow.py b/libroar/RoarCanvasWindow.py
index 6dcb5a5..dde9b0b 100644
--- a/libroar/RoarCanvasWindow.py
+++ b/libroar/RoarCanvasWindow.py
@@ -47,6 +47,8 @@ class RoarCanvasWindow(GuiWindow):
 
     # {{{ applyTool(self, eventDc, eventMouse, keyChar, keyModifiers, mapPoint, mouseDragging, mouseLeftDown, mouseRightDown, tool, viewRect)
     def applyTool(self, eventDc, eventMouse, keyChar, keyModifiers, mapPoint, mouseDragging, mouseLeftDown, mouseRightDown, tool, viewRect):
+        if mapPoint != None:
+            mapPoint = [a + b for a, b in zip(mapPoint, viewRect)]
         dirty, self.canvas.dirtyCursor, rc = False, False, False
         self.canvas.journal.begin()
         if eventMouse: