Consider about a study note with 10 documents.
If we search a word in the 1st tab (1st document) and then if we want to look at the search results for 8th or 9th tab(document) we have to scroll down insanely.
Therefore search across all documents function has become useless even with a moderate size search result.
My suggestions for this issue-
“Skip to next document” and "skip to previous document) options for the search panel.
Search results appear as toggle list for each document(tab).
When changing the tab, search results change for the document accordingly.