WindhawkQTTabbar and some other tools provide a feature where double-pressing F2 to rename a file first selects the base name (existing Explorer behavior) but the second press selects just the extension. That's handy to e.g. rename a zip file to a cbz file. This mod implements that same feature: double-press F2 in Explorer to rename a file's extension.
Since version 2, triple-pressing F2 selects the full name. Subsequent (>3) presses repeat the cycle by selecting the base name again (Explorer default behavior), then the extension, then the full name, etc.
Since version 2.1, you can choose to invert this cycle: select the full name with 2 presses, the extension with 3 presses.
Since version 3, you can enable continuous looping: every F2 press steps to the next selection in the cycle, regardless of timing. If the selection at the moment of such a keypress is not one of the steps (e.g. you manually changed it to something random), the loop starts over.
This mod works great together with extension-change-no-warning.