S E C T I O N H .3
1113
Implementation Notes
75. Acrobat viewers report an error when a user activates an outline item
whose destination is of an unknown type.
76. Acrobat viewers up to version 3.0 ignore the
PageLabels
entry and label
pages with decimal numbers starting at 1.
77. In PDF 1.5, the order of moving the keyboard focus between annotations
on a page by using the tab key can be made explicit by means of the page’s
Tabs
entry (see Table 3.27). In earlier versions, the tab order was not ex-
plicitly specified and depended on the viewer. In Acrobat 4.0, the order in-
cludes only widget annotations and is determined by their order in the
page’s
Annots
array. In Acrobat 5.0, the order includes all annotations:
widgets come first and are ordered as in Acrobat 4.0; other annotations
come after widgets and are ordered by rows. Acrobat 6.0 has the same be-
havior as Acrobat 5.0 for documents that do not contain a
Tabs
entry. For
documents that have a
Tabs
entry, Acrobat 6.0 reorders widgets in the
Annots
array to match the specified order (row, column, or structure) so
that the tab order for widgets is preserved when the document is opened
by earlier viewers.
78. Acrobat viewers update the annotation dictionary’s
M
entry only for text
annotations.
79. Acrobat 2.0 and 2.1 viewers ignore the annotation dictionary’s
AP
and
AS
entries.
80. All versions of Acrobat through 6.0 ignore the
AP
entry when drawing the
appearance of link annotations.
81. Acrobat viewers ignore the horizontal and vertical corner radii in the an-
notation dictionary’s
Border
entry; the border is always drawn with square
corners.
82. Acrobat viewers support a maximum of ten elements in the dash array of
the annotation dictionary’s
Border
entry.