TAB: time sigs not created

Context: commit 82bd308 (2013-03-16)

Steps:

1) Create a new score using the "Guitar (tablature)" instrument (or any of the "... (tablature)" instruments).
2) In "Styles | Edit staff types", turn on the "Show time sigs" check box.

Result: No time sig is shown.

This is because the time signature element is not even created when the score is created; then, the TAB drawing routines have nothing to show / hide in the first place.

M.