The current behavior is that the cursor goes to the very end of the HTML.
My suggestion is that when your cursor is in the WYSIWYG field, and you open the HTML editor, the cursor should be in the place within the HTML that corresponds to the place it was in the WYSIWYG field.
Example (| represents the cursor):
I don’t know how feasible it is, but I think it would be very useful.
This would be a nice improvement. One question to think about in the implementation would be the following: If the HTML text box is open, then would the cursor move around as you edit the WYSIWYG text?
I think it would make sense, since any content changes made in the WYSIWYG are immediately reflected in the HTML (and vice versa). It would follow that principle if the cursor was always synced, too.
But perhaps it is more difficult to implement.