wx.Image.FindFirstUnusedColour and colour depth

Roger Binns wrote:

Robin Dunn wrote:

* In 2.5 you can create wx.Bitmaps that don't match the screen depth,
so you might try using a depth of 24 for the two bitmaps and see if
that works.

bitmap = wx.EmptyBitmap(usewidth, useheight, 24)

That worked perfectly and only required inserting 4 characters. Thank
you.

Well, it worked perfectly on Windows anyway. Linux gives an assertion
failure if the depth doesn't match the display depth.

PyAssertionError: C++ assertion "wxAssertFailure" failed in ../src/gtk/bitmap.cpp(310):
  invalid bitmap depth

Fortunately I only need the code to work on Windows (the transparency stuff
fails for non-Windows platforms in wx.ListCtrl so I use an alternate strategy
for them anyway).

Roger