planner.Header.AutoSize when changing orientation

When changing the orientation of the planner in type day - i.e. planner.Sidebar.Position := spTop; the header does not autosize to increase its width in this situation. i.e. 5 positions with Monday - Friday in the header, when it rotates the header text is truncated.

I have tried increasing the height but that doesn't give me what is needed. The following have also been set but no success:
               planner.Header.AutoSize  := True;
               planner.Header.AllowResize := True;

What property do I need to set?

Header.Autosize = true will adapt the header size according to the nr. of items in the header and not to the length of the text in the header. There is currently unfortunately not a built-in function to have the Planner perform autosize based on text in the header.