Hi lyx-devel, It would be useful to support this feature because we could perform a replace-all within a selection and quickly achieve the desired result without clobbering the rest of the document.
The find-and-replace dialog could support a checkbox labelled "In selection" which should be enabled and checked if the user invoked this with an active selection. It should be disabled if there is no selection. Shall I file this request on trac if you think users might find this useful? Thanks, Manoj