* gdbtk.tcl (delete_expr): Unset corresponding element of

	* gdbtk.tcl (delete_expr): Unset corresponding element of
	expr_update_list when destroying an expression.
	(create_expr_window): Initialize expr_num, delete_expr_num,
	and expr_update_list here when each new expression window
	is created, rather than once at startup.
PR 9383