I just did this in a sample project.
When I apply a condition to a block level style (div.hideme), I see the background color showing a condition has been applied:
When I apply a condition to an inline style (span.NoteToReviewer), I see a condition box to the left of the span's condition:
Two settings control how these are displayed: First, ensure you have the "show/hide conditions" option selected at the bottom of the Flare XML editor -- but even then, that just disabled the background colors for block-level styles. It didn't remove the condition indicator for the inline style.
Second, make sure you have this option enabled (so you can see the box next to the span that has the condition applied):