The Zoom View contains not more than 20 rows by default. The rest rows are available by scrolling.
To change this behavior use the Manage Rows in Zoom View menu button on a sequence toolbar:
When the Show All Rows item is checked all available annotations are always shown. You can also add rows by selecting the +5 Rows and +1 Row items and remove rows by selecting the -5 Rows and -1 Row items. To restore the default number of rows select the Reset Rows Number item.
See also: