Rulers in Writer are blank

[esebm]

Hi, I'm using LO 5.1.4.2 in win 10 64bit.
The vertical and horizontal rulers are blank, the small dividing lines are not visible.
Is there a setting to show/hide them?
Thanks,
Ed

[jrkrideau]

See View > Rulers

[RoryOF]

You may need to change your Windows Theme.

[esebm]

Both rulers are checked in View > Rulers.
Changing the windows theme does not make any difference. And I really don't understand why LO would change its look depending on windows.

[RoryOF]

Changing a theme can affect toolbars, icons, system fonts and colours.

[esebm]

I've played around with the themes and it doesn't make difference.