But that is not the function of the F8 key, which is to extend a selection. See:
https://support.office.com/en-us/art...-f762f663ceb2?
I should also point out that, as coded, the dropdown will only let you choose one entry per document and that, every time you open the document, the dropdown list will be reset. To prevent that, you would need to save the document as a template and make some coding changes. The advantage is that the macro now only needs to exist in the template - the documents it creates can all be saved in the docx format. See attached.