I'd second that.
For the moment, it is possible to do that via a Google site search (not that I'd endorse it), though it is likely to produce bad results with tropers whose handles are similar to common words.
Fanfic Recs orwellianretcon'd: cutlocked for committee or for Google?I tried using a Google Site Search once, but it didn't really work.
Of course it's not perfect. It requires that the thread has been crawled, that one uses the advanced options to limit the scope of the search (specifically, inurl:https://tvtropes.org/pmwiki/posts.php?discussion={id_of_thread} ), and that the search keywords actually prove to be relevant (looking for eg.: "avatar" will produce no useful resuslts because of the thread avatars, for example). It's still a regular-to-good last choice to have.
Fanfic Recs orwellianretcon'd: cutlocked for committee or for Google?Yeah, I have no idea what you just said there, but it sounds like "There's already an option, so it's low on the list of things to do."
This has been submitted to Wishlist; locking.
We have a "Search for posts by troper" feature, but is it possible to have a "Search for posts by troper within this thread" feature?