Probably because the timeline can know if a clip is "missing" precisely because that clip is present in a loaded event browser, but not in that particular project. But I don't think the event browser has any way to know if a clip outside of it's database should or shouldn't exist.
I suspect what you're looking for is a way for X to report back upstream to the event browser which clips do or don't appear in a particular project - but since any project can be linked to multiple events that's kinda complex. Where does the "missing" indicator show up? The whole relational thing makes this perhaps a bit more dicey than it otherwise might appear.
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Hey Bill, thanks for the reply. You're actually a little bit off of what I'm looking for.
I have a single event and a single project with media used from event to project. I can go to the timeline index and search the word "missing" and it comes up with every clip that has missing media. I go to the event and I can see exclamation marks on all the missing media but when I do a keyword search for "missing" In the event browser, it returns no results even though there are missing clips in the event browser. It seems like if it should do it in the timeline then it should also do it in the event browser.