To set preferences for form display and filling, choose File > Options > Forms.
Automatically calculate field values
Enable this to have mathematical operations assigned to form fields automatically updated, if these exist in an active PDF file you open in the program.
Display focus rectangle
Enable this to see which form field currently has the focus during form filling.
Highlight Form fields
Select highlight preferences for form fields. The following options are available:
Show hover text for fields on cursor entry
Use this checkbox to have hover text displayed or hidden for a form field being filled. To specify hover text for a form field, use its Properties dialog box. The text might be the field name or filling instructions.
Field highlight color
Specify a background color for form fields when highlighting is ON.
Required field border color
Set a separate field border color for required form fields.
Auto-Complete
Select this to have entries typed during form filling matched with previous entries so they are automatically completed. This means frequently used names, addresses and numbers can be selected, not typed. Enable or disable the memory for numerical items. You can edit the memory list.
See also Filling Forms and About PDF Forms.