pdf-association
What does multi-select mean on a combo box field?
32K-2, 12.7.5.4, Choice Fields, addresses both scrollable list boxes as well as combo boxes. In table 233 of that section, it lists the field flags specific to choice fields - one of which is MultiSelect.
What does it mean to have this on a combo box? What is presented to the user in this case? What is the expected AP for such an annotation?
I'd like to propose that we restrict this value to ONLY list boxes, based on it not making sense for combo boxes and, AFAICT, no implementations actually support such a scenario.
Just noting that some UI frameworks do support multi-selection combo boxes, even if the common O/Ses don't. But I agree they are a far less common UI metaphor so platform independence and interoperability are considerations. A possible upside is that a multi-select combo box can take up less screen space (single row) than a typical list box.
From Table 233 Bit 22 MultiSelect
Was:
(PDF 1.4) If set, more than one of the field’s option items may be selected simultaneously; if clear, at most one item shall be selected.
Proposed:
(PDF 1.4) If set, more than one of a list box option items may be selected simultaneously; if clear, at most one item shall be selected.
There is a related problem with the text describing the /I key in table 234.
The /I key is needed for the case where the list of options (/Opt) has duplicate values. /I tells the processor the index(es) of which one is selected. The wording for the key is specific to the multi-select case. But a single select combobox may also have duplicate entries.
Was:
(Sometimes required, otherwise optional; PDF 1.4) For choice fields that allow multiple selection (MultiSelect flag set), an array of integers, sorted in ascending order, representing the zero-based indices in the Opt array of the currently selected option items. This entry shall be used when two or more elements in the Opt array have different names but the same export value or when the value of the choice field is an array. If the items identified by this entry differ from those in the V entry of the field dictionary (see discussion following this Table), the V entry shall be used
Proposed:
(Sometimes required, otherwise optional; PDF 1.4) For choice fields, an array of integers, sorted in ascending order, representing the zero-based indices in the Opt array of the currently selected option items. This entry shall be used when two or more elements in the Opt array have different names but the same export value. For populated fields that do not allow multiple selection (via MultiSelect flag) the array shall have a single entry. If the item(s) identified by this entry differ from those in the V entry of the field dictionary (see discussion following this Table), the V entry shall be used
TWG asks that @JohnBrinkman and @lrosenthol work on the proposed text for the /I key.
Fix for Table 234 applied.
Waiting on @JohnBrinkman and @lrosenthol for the proposed text for the /I key.