In case anyone is interested in this non-printing characters (NPCs) colour issue in LO. I just stumbled across a solution to the NPCs being the horrible blue colour they are. That said the solution then raises an issue all of its own.
To get the NPCs to show up black (not blue) launch Writer then go menu:
Tools > Options > LibreOffice > Accessibility >
Options for High Contrast Appearance > Use automatic font colour for screen display
And put a tick in that box. Once done click “OK” to exit the Options. Then shut down Writer. Then re-launch Writer. Now the NPCs will show up as black. Fine that’s a solution to the NPCs colour problem.
However, now if you enter in any text that is a font colour different to the default (“Automatic”) colour then the text will not show up as the colour you chose – you will actually be entering text in the font colour you chose, it just won’t display as such. To get it to display you need to go back to the setting described above, untick it, shut down Writer, then re-launch Writer. Now your different colour font will be displayed - but you’ll be back with the blue NPCs again.
As I don’t use different font colours this isn’t an issue for me but it might be for some folks.
Windows 7 Pro. x64 SP1
Apache OpenOffice Portable [PortableApps] 4.1.5