DatePicker not working

Question

Apex 4.1
I have created an application page with two date picker items, but when I click in the items the calendar popup does not appear.
I've tried different values for the "Show" option - on focus, on icon click, both, and inline. The calendar icon never gets shown. If I choose "inline" the item disappears entirely.
If I change them to use the classic date picker item type, they work. But I'd prefer the new date picker.
Edited by: Jeff Kemp on Dec 30, 2011 4:23 PM

Answer 1

I found the cause of the problem by clearing all the item properties and re-setting them one by one.
Extra information: I also found this problem caused all popup items, not just date pickers, to stop working.
I had the following properties set on the date picker item:
Show Other Months: yes
Number of Months: 1,3
If I set Number of Months to just "3" (without the quotes), all the popup items on the page start working as before.
The help message for the "Number of Months" parameter states:
"Set how many months to show at once. The value can be a straight integer, or can be a two-element array [row,column] to define the number of rows and columns to display.
example
[2,3] - will display months in 2 rows and 3 columns."
The problem occurs when I omit the brackets [ and ] from the parameter value. This appears to be a bug in Apex. Apex should validate the option, or at the least give a runtime error, that gives a clue as to (a) which item has the faulty parameter value, and (b) what the problem with the value is (e.g. "invalid Number of Months option on item P1_XYZ").
As it stands now, you have to guess (or determine by painstaking elimination, as I did) which item is causing all the popups to not work.