wxpython：按钮上的透明背景

Question

Button1是一个没有背景的png，但它显示为灰色背景，我尝试将其设置为透明，但这只是给它一个黑色背景。

如何使按钮背景透明？

import wx

class windowClass(wx.Frame):

    def __init__(self, *args, **kwargs):
        wx.Frame.__init__(self, None, -1, 'test', size=(1000, 600))

        display_size = wx.DisplaySize()
        print display_size
        path = "background.png"
        bg = wx.Image(path, wx.BITMAP_TYPE_ANY)
        bg = bg.Scale(display_size[0],display_size[1]).ConvertToBitmap()
        self.back = wx.StaticBitmap(self, -1, bg, pos=(0,0))

        path1 =  wx.Image("button.png")
        path1.Rescale(100, 100)
        image1 = wx.BitmapFromImage(path1)

        self.button1 = wx.StaticBitmap(self.back, -1, image1, (10, 10))
        self.button1.Bind(wx.EVT_LEFT_DOWN, self.button1Click)
        self.button1.SetBackgroundColour(wx.TransparentColour)

        self.Show()

    def button1Click(self,event):
        self.Close()

def main():
    app = wx.App()
    windowClass(None)

    app.MainLoop()

main()