Kai, as far as I know, the Character Styles panel does not show you which character style is applied via a GREP style even if you highlight the text.
‘Feature-or-a-Bug’?
I think it is a feature.
Character styles applied via GREP styles are handled differently than regular character styles. While regular character styles are ‘dynamic’, character styles applied via GREP styles are ‘static’. For instance, you can’t apply two character styles to the same text, but you can apply two GREP styles to the same text with two separate character styles. In fact, you can even apply another character style manually to text that is already formatted with a different character style applied via a GREP style. If you decide to override a GREP style instance, you can’t, because it’s static. (You can in fact apply different local formatting to it, but that will be considered as an overridden paragraph style. But you can’t apply the [None] character style to remove the style entirely.)
So with this in mind, the InDesign team felt that it does not make sense to treat it as a regular character style. So therefore, when you select such text, its character style does not show up in the character styles panel. And for the same reason, when you do a Find Format search in Find/Change with this character style, the Find/Change will not find it even if it’s definitely applied to text in the document.
Do I agree with their choice? Not really. But I believe that this was their reasoning behind it. (Unless it is really a bug…)
Ari