Term completion. Typing ^TAB (Control + Tab) in the simple search entry field while entering a word will either complete the current word if its beginning matches a unique term in the index, or open a window to propose a list of completions
Picking up new terms from result or preview text. Double-clicking on a word in the result list or in a preview window will copy it to the simple search entry field.
Disabling stem expansion. Entering a capitalized word in any search field will prevent stem expansion (no search for gardening if you enter Garden instead of garden). This is the only case where character case should make a difference for a Recoll search. You can also disable stem expansion or change the stemming language in the preferences.
Phrases. A phrase can be looked for by enclosing it in double quotes. Example: "user manual" will look only for occurrences of user immediately followed by manual. You can use the This exact phrase field of the advanced search dialog to the same effect. Phrases can be entered along simple terms in all simple or advanced search entry fields (except This exact phrase).
Browsing the result list inside a preview window (1.5). Entering Shift-Down or Shift-Up (Shift + an arrow key) in a preview window will display the next or the previous document from the result list. Any secondary search currently active will be executed on the new document.
AutoPhrases (1.5). This option can be set in the preferences dialog. If it is set, a phrase will be automatically built and added to simple searches when looking for Any terms. This will not change radically the results, but will give a relevance boost to the results where the search terms appear as a phrase. Ie: searching for virtual reality will still find all documents where either virtual or reality or both appear, but those which contain virtual reality should appear sooner in the list.
Finding related documents. Selecting the Find similar documents entry in the result list paragraph right-click menu will select a set of "interesting" terms from the current result, and insert them into the simple search entry field. You can then possibly edit the list and start a search to find documents which may be apparented to the current result.
File names. File names are added as terms during indexing, and you can specify them as ordinary terms in normal search fields (Recoll used to index all directories in the file path as terms. This has been abandoned as it did not seem really useful). Alternatively, you can use the specific file name search which will only look for file names and can use wildcard expansion.
Query explanation. You can get an exact description of what the query looked for, including stem expansion, and Boolean operators used, by clicking on the result list header.
Closing previews. Entering ^W in a tab will close it (and, for the last tab, close the preview window). Entering Esc will close the preview window and all its tabs.
Quitting. Entering ^Q almost anywhere will close the application.