I'm having the same problem since I switched to a darker theme. The problem with the tab texts is the foreground color is taken from system colors while the background color/image is hardcoded. I don't know if a configurable solution exists but what I did was to find the piece of code that is responsible for the text color and change it inside the CB source. What I did was switch to 'Visual Studio 7.1' style in 'settings->environment->notebooks appearance->tabs style' and change line 187 & 381 in 'src/src/notebookstyles.cpp'
from:
dc.SetTextForeground(wxSystemSettings::GetColour(wxSYS_COLOUR_BTNTEXT));
to:
dc.SetTextForeground((page.active) ? wxSystemSettings::GetColour(wxSYS_COLOUR_BTNTEXT) : *wxBLACK);
and rebuild.
I don't have a solution for the icons.