There’s a gray background appearing by default behind the Rubies text.
When I modify the Rubies character style, I see in the “contains” section a mention of a Shadow: Gray setting.
I can’t locate where this setting is supposed to be modified.
All other settings that I modify in the Rubies char style are reflected in my document as expected.
Rubies are fields. As such, they are indicated by the grey background on screen (to let you see the fields easily in the text), and would not have the background when printing/exporting to PDF.
If you really need to hide the highlighting (which is not the best thing to do, along with hiding formatting marks and so on, the tools helping you to see the actual structure of your documents), then there’s View|Field Shadings menu selector for you.
