This could be implemented many different ways, but the simplest and most straightforward and intuitive is probably something like this:
- An internal list of "hidden" items is created in memory (or some cache or other)
- Any files currently cached in the "hidden" list are excluded from the results, even if they match the search criteria
- Add a "Hide Items" option to the Right-Click context menu on result items
- When "Hide Items" clicked, the right-clicked & other selected files are added to the "hidden" list and thus removed from the visible results list
- Add a menu option to "Show Hidden Items" which when clicked, manually empties the "hidden" list even if the search hasn't changed
- When the Search string (or any search options) changes, the hidden list is cleared and all matching files are displayed again
Note: The inspiration for this feature comes from WinMerge; I use this feature constantly and regularly find myself looking for such an option in Everything!