Gmail on S8 not allowing account selection

[Android Central Question]

So, have had this new S8 for two weeks and from the get-go it will not allow me to choose accounts if I choose share a doc from any app. By this I mean that if I went to Gallery and chose a photo to share via Gmail, Gmail opens but the drop-down menu for my other two accounts is inactive. However, if I open Gmail first, the drop-down menus appear.

It's driving me daft. Any ideas??