Item Ids can only have four letters, the corresponding ID for this field is "sdNum" - and therefore five characters long.
The "item_id" "sdNum" is too long. It can only be 4 characters in length.
Also, there's no need to define an item_id property for static_text elements.
I cannot stop myself saying a big thank you to you. You told such an important point none can think of it. Exactly four letters for item id, I read this and tried 3 letter that even did not work.
This should be well document and really a stupid one limitation for acro dialogs.
However thank you very much.
Dialog box items are identified by an ItemID, which is a unique 4-character string. An ItemID is necessary
only if the element must be referred to elsewhere in the dialog box description (for example, to set or get a
value for the element, to add a handler for the element, or to set a tab order including the element).
thank you Gilad.