Panel display not reading cfg files correctly?

Before I log this as a bug, I wonder if anybody else is seeing this. I have reproduced it on two systems.

TB 2.6.1
FreePBX 2.5.0rc2.0

I have heavily modified op_style.cfg and op_button.cfg files (and also

If I access the FOP from within the TB menu (PBX/Panel) then it all displays fine with my amendments.

If I access it directly (using http://trixbox.ip/admin/panel.php) then I only get the default style settings.