Operating system: macOS 11.4
wxPython version & source: 4.1.1
Python version & source: 3.7.0
Description of the problem:

Looks like "wx.TheClipboard.IsSupported(wx.DataFormat(wx.DF_TEXT))" always return false even if it does has text in clipboard.

For example, first copy some text to clipboard; however the following code doesn't print anything

wx.TheClipboard.Open()
if wx.TheClipboard.IsSupported(wx.DataFormat(wx.DF_TEXT)):
    data = wx.TextDataObject()
    if wx.TheClipboard.GetData(data):
        print(data.GetText())
wx.TheClipboard.Close()

The following code print the text in clipboard correctly

wx.TheClipboard.Open()
data = wx.TextDataObject()
if wx.TheClipboard.GetData(data):
    print(data.GetText())
wx.TheClipboard.Close()