import wx

class Draggable(wx.Panel):
    def __init__(self, parent, size):
        wx.Panel.__init__(self, parent, size=size)
        self.SetBackgroundColour(wx.BLACK)
        self.Bind(wx.EVT_LEFT_DOWN, self.OnClick)
        self.Bind(wx.EVT_LEFT_UP, self.OnRelease)
        self.Bind(wx.EVT_MOTION, self.OnMouseMove)
    def OnClick(self, e):
        self.clickDelta = e.GetPositionTuple()
        self.oldPos = self.GetPositionTuple()
        self.SetBackgroundColour(wx.WHITE)
        self.Refresh()
    def OnRelease(self, e):
#        self.SetPosition(self.oldPos)
        self.SetBackgroundColour(wx.BLACK)
        self.Refresh()
    def OnMouseMove(self, e):
        if e.Dragging():
            dx, dy = self.clickDelta
            mx, my = e.GetPositionTuple()
            x,y = self.GetPositionTuple()
            x += mx-dx
            y += my-dy
            self.SetPosition((x,y))
            self.Refresh()

class Frame(wx.Frame):
    def __init__(self):
        wx.Frame.__init__(self, None, -1)
        sizer = wx.BoxSizer(wx.VERTICAL)
        self.SetSizer(sizer)

        d = Draggable(self, (50, 50))
        d.SetPosition((50, 50))

class App(wx.App):
    def OnInit(self):
        f = Frame()
        self.SetTopWindow(f)
        f.Show()
        return True

app = App(0)
app.MainLoop()