I want to add a white color to the thickness box which is currently appearing as grey as in the image. Any help to solve

[![enter image description here](https://i.stack.imgur.com/xmH3V.jpg)](https://i.stack.imgur.com/xmH3V.jpg)

Below is the code

```
sbSizer4 = wx.StaticBoxSizer( wx.StaticBox( self.m_panel_geometry, wx.ID_ANY, u"Thickness" ), wx.VERTICAL )
sbSizer4.Add( ( 0, 0), 1, wx.EXPAND, 5 )
m_thicknessChoices = [ u"0.062 in", u"0.031 in" ]
self.m_thickness = wx.Choice( sbSizer4.GetStaticBox(), wx.ID_ANY, wx.DefaultPosition, wx.DefaultSize, m_thicknessChoices, 0 )
self.m_thickness.SetSelection( 0 )
#self.m_thickness.SetBackgroundColour(wx.Colour(240, 0, 240)) 
sbSizer4.Add( self.m_thickness, 0, wx.ALIGN_CENTER|wx.ALL|wx.EXPAND, 15 )
sbSizer4.Add( ( 0, 0), 1, wx.EXPAND, 5 )
bSizer11.Add( sbSizer4, 1, wx.ALL|wx.EXPAND, 10 )
bSizer9.Add( bSizer11, 1, wx.EXPAND, 5 )
bSizer12 = wx.BoxSizer( wx.HORIZONTAL )

```