Hi Jongware,
I'm 100% sure that the Style Override Highlighter was enabled with that document the OP is showing.
And the OP perhaps opened an IDML document from a doc where the feature was enabled.
In InDesign versions before CC 2015.3 the highlighting is done in red.
With CC 2015.3 and newer the highlighting is done in blue.
Officially the feature was introduced with CC 2015.3.
In versions before it can be controlled only by using scripts.
Here a comparison.
CS4 to CC 2015.2:
Image may be NSFW.
Clik here to view.
CC 2015.3 and above:
Image may be NSFW.
Clik here to view.
Regards,
Uwe
