Fix a Blank or Incorrect Modern Combo Box in Power Apps

A modern combo box usually appears blank because its selected record does not match the shape of its Items table, the display formula points at the wrong field, or the user cannot read the source. Do not fix it by loading the whole source into App.OnStart until you know which boundary failed.

Know the important properties

For the current modern combo box:

• Items must return a table.
• ItemDisplayText decides what each row displays and uses ThisItem.
• DefaultSelectedItems must return a table of records matching Items.
• Selected returns the last selected record.
• SelectedItems returns the selection table.
• SelectMultiple controls single or multiple selection.
• IsSearchable controls search.

Some modern-control properties have been renamed. Check Microsoft's current property table rather than adapting a screenshot from an older studio version.

Start with a simple text table

For a SharePoint list named Departments with a Title column:

Items = SortByColumns(Departments, "Title")
ItemDisplayText = ThisItem.Title

For a single-select default based on an existing department ID:

DefaultSelectedItems =
If(
    IsBlank(ThisItem.DepartmentId),
    Blank(),
    Filter(Departments, ID = ThisItem.DepartmentId)
)

DefaultSelectedItems expects a table. Filter returns a table even when one record matches. A common failure is supplying a text value such as ThisItem.DepartmentName when Items contains complete SharePoint records.

For a SharePoint Choice field

Use the choices table:

Items = Choices(Requests.RequestStatus)
ItemDisplayText = ThisItem.Value

Inside a form, the generated card normally supplies a matching DefaultSelectedItems record. If you replace that formula, inspect the card's Parent.Default shape before writing a lookup.

Why it works for the owner but not users

The app owner may have access to both the app and SharePoint source while an end user has only the app. Sharing does not grant data permission.

Test the combo box under an ordinary user's identity. Confirm that person can open the list and read the columns used by Items and ItemDisplayText. If item-level permissions apply, a shorter list may be correct rather than broken.

Do not use a collection populated by the owner's connection to bypass that boundary.

Search and delegation

Modern combo boxes can search, but large-source behaviour depends on the Items formula and connector. Microsoft recommends server-side filtering through SearchText for very large data sets.

Avoid wrapping a delegable source in transformations that force local processing. Watch the formula bar for delegation warnings and test with records beyond the local row limit.

A five-minute diagnosis

1. Add a temporary gallery with the same Items formula.
2. Put a label inside it using the proposed display field.
3. Add a label showing JSON(ComboBox1.Selected, JSONFormat.IndentFour) in a development copy.
4. Compare DefaultSelectedItems with an actual row from Items.
5. Test under the affected user's identity.

Remove diagnostic labels before publishing because selected records can contain personal or confidential data.

Recovery boundary

If the modern control changed during an update, compare the current property names and test a classic combo box in a copy of the screen. Do not replace the production control until defaults, search, accessibility, form updates and mobile behaviour all pass.

For help debugging the exact record shape rather than guessing at formulas, join the Power Apps Builders Space.

Sources

• Modern combo box control
• Classic combo box control
• Choices function
• Delegation overview
• Share a canvas app