As per the discussion from How do you search Your Private Messages?:
I’m referring to this function is working (when you search in your messages page):
However, Advanced Search is not being triggered properly.
When you search in a category, you see this:
Which results in Advanced Search being triggered and opening up against the results list with the appropriate search selection (category filters) applied:
Same with search in a user page:
However when you search in private messages Advanced Search is not triggered properly, is when it opens nothing gets applied in Adanced Search … so it’s not at all clear why it’s being triggered in the first place, which is really confusing 
In fact the search term being applied in the search box is “private_messages:{username}” whereas the search term applied when you tick the corresponding advanced search option (“Only return topics/posts… In my messages”) is “in:private”
So, in summary a fix to this would be, when you search from Messages page and click “Search messages” tickbox, Advanced Search opens up with the correct search selection applied, like this:
i hope that’s all clear… it would certainly help our users (and other users relying on private messaging) at lot.
Thanks!
