When performing a search or replace with the Find and Replace tool window, SlickEdit can use the previous search/replace string for the next search/replace operation. To enable this option, from the main menu, click Tools > Options > General, select the Search tab, then select the option History retrieval. Now when you press Ctrl+F, the previously used search string is displayed in the Search for field of the Find and Replace tool window.
Note that if the option Selected text (if exists) is checked, the currently selected text is used as the search/replace string instead. In this case, the word at the cursor is only used if there is no current selection.