Combo subfield with showIf condition based on a parent field is not saved

[Remco646]

Short description of the issue

A Combo field subfield with a showIf condition referencing a field outside of the Combo field is displayed correctly in the admin UI but is not saved when the page is saved.
The following error is displayed:
InputfieldForm: Warning ('showIf' from 'subfield'): dependency field 'toggle_field' is not present in this form.

Expected behavior

• The Combo subfield should be shown or hidden correctly in the admin UI based on the showIf condition.
• The subfield value should be saved correctly when the page is saved.

Actual behavior

• The Combo subfield visibility updates correctly when editing the page.
• When saving the page, the value of the subfield is not saved.

Steps to reproduce the issue

1. Create a checkbox field named toggle_field
2. Create a Combo field named combo_field with the following subfield:
   • subfield (Text field, with showIf="toggle_field=1")
3. Create a template named test_template and assign these fields:
   • toggle_field (Checkbox)
   • combo_field (Combo field)
4. Create a page using test_template.
5. Edit the page in the admin UI:
   • Check toggle_field: subfield appears.
   • Enter a value into subfield.
   • Save the page.
   • The value entered in subfield is lost after saving and an error is shown.

Setup/Environment

• ProcessWire version: 3.0.244
• ProFields: Combo version: 0.1.7