D11263 already polished handling of the Settings → Configure → Advanced → History checkbox, i.e. unchecking that setting clears recent files, recent folders and the last used directory for copy/move/link.

Remaining issues:

• 1. Even after unchecking the checkbox, File → Open / Save As / … still saves filenames to the [KFileDialog Settings] group. We can check whether this can be prevented, but otherwise it's not really an important issue, or at least not something which can be solved in Gwenview.
• 2. File → Open Recent → Clear List clears the list, but the same list in the Start Page → Recent Files tab is only cleared after restarting Gwenview.
• 3. The context menu for the Recent Files tab is broken, it should contain Forget this File and Forget All Files like in KDE4.
• 4. For the Recent Folders context menu, the last action should be renamed to Forget All Folders.
• 5. File → Open Recent should also make it possible to forget all folders, either by adding a separate action or by extending the behaviour of the (to be renamed) existing action.