After activating AcePaste, AceType or AceEdit, you can click the AcePaste Now button on the main toolbar to send the selected clip to the application you were working with when you activated AcePaste, AceType or AceEdit. You can achieve the same by double-clicking the clip, pressing Ctrl+Enter on the keyboard, or invoking the AcePaste/AceType/AceEdit keyboard shortcut again.
When the Double-Click Sends Clip mode is active, you can also click the AcePaste Now button to send the active clip to the previously active application.