Power Apps Modern Controls & UI: Combobox Gotchas and What to Do When Things Change

Why this exists: You're building or maintaining a Power Apps canvas app. The combobox looks different. Or you can't uncheck items the way you expected. The community forums are full of these questions—and the answers often depend on which combobox you're using and when it was last updated.

For you if: You work with Power Apps canvas apps, especially Copilot-generated pages or apps built with modern controls, and you've run into combobox behavior or appearance surprises.

The Two Problems People Keep Hitting

Problem 1: "I can't uncheck items in my combobox." Modern combobox controls have gone through several iterations. Some makers report that clicking a selected item doesn't deselect it—or that the behavior changed after an update.

Problem 2: "The combobox in my Copilot-generated app suddenly looks different." Copilot-generated Power Apps pages use modern controls. When Microsoft rolls out UI updates, those controls can shift appearance overnight—without you changing anything.

Both are real. Both are fixable if you know where to look.

Ground Truth: What the Modern Combobox Is Supposed to Do

Microsoft's modern combobox documentation states:

Toggle selection behavior: Clicking a selected item now unselects it, making it easier to remove selections without clearing the entire list.

SelectMultiple defaults to true. If your app requires single selection, explicitly set SelectMultiple = false.

So in the current version, unchecking by clicking a selected item is intentional. If that's not happening in your app, you're likely running into one of these:

• Control version mismatch – Copilot-generated apps or older canvases might reference an older control version that didn't have toggle behavior.
• Single-select mode – With SelectMultiple = false, selecting a new item replaces the previous one; there's no "uncheck" because only one item can be selected at a time.
• DisplayMode – If the control is in View or Disabled mode, selections can't be changed at all.

Workarounds When Uncheck Doesn't Work

1. Confirm You're Using the Modern Combobox

In Power Apps Studio, add a combobox and check whether it's the Combo box modern control (from the modern controls set) or the legacy Combo box control. The legacy control has different properties and no built-in multi-select uncheck by default.

Fix: Enable modern controls via Settings → Updates → Modern controls and themes, then add the combobox: Insert → Input → Combo box.

2. Add a Clear Button

If toggle behavior is unreliable—or you want a fallback—add a Clear or Reset button and set its OnSelect to:

Reset(YourComboBoxName)

Reset() clears both the selection and the search text. It's explicit and always works.

3. Use DefaultSelectedItems + SelectedItems for Programmatic Control

If users need to remove specific items (rather than clear all), you can drive the combobox from a collection and manage removals yourself:

• Store selections in a collection, e.g. ClearCollect(SelectedItems, ComboBox1.SelectedItems)
• For removal: Remove(SelectedItems, LookUp(SelectedItems, ID = ItemToRemove.ID))
• Set the combobox DefaultSelectedItems to your collection and refresh when you change it

This is more complex but gives you full control when the built-in toggle is flaky.

4. Check SelectMultiple and DelayOutput

• SelectMultiple = true – Users can select/deselect multiple items; toggle should work.
• SelectMultiple = false – Single selection only; "uncheck" means picking a different item (or none, if your data allows).
• DelayOutput = true – OnChange fires only when the user clicks outside or presses Enter. If you're doing something important in OnChange, make sure your logic accounts for the user's final state, not intermediate clicks.

When the Combobox Looks Different

Copilot-generated Power Apps pages pull from Microsoft's evolving design system. When the platform updates the Fluent UI or modern control styling, your app inherits those changes. You didn't break anything—the platform moved.

What You Can Control

Note: Microsoft renamed some properties in recent updates. If you see errors like "FontColor not found," use Color instead. Similarly: FontSize → Size, BorderRadius → RadiusTopLeft, etc. See the property renames table in the combobox docs.

If You Need Consistency Across Rollouts

1. Lock appearance explicitly – Set Appearance, BasePaletteColor, and Size in your app so updates don't surprise you.
2. Document your control version – In the modern controls set, note which version you're using (e.g. ModernCombobox@1.0.0) so you can track behavior changes.
3. Expect some drift – Platform updates will occasionally change defaults. Governance that keeps an eye on "what changed" (release notes, testing in a sandbox) pays off here.

Quick Reference: Modern vs. Legacy Combobox

When to Escalate

• Control doesn't exist in your environment – Modern controls require a supported Power Apps plan. Check modern controls overview for requirements.
• Behavior differs from docs – File feedback in the Power Apps community forum. Include control version, SelectMultiple setting, and steps to reproduce.
• Copilot-generated app broke after an update – Regenerate the page if possible, or manually update the control properties. Copilot output will evolve; treat it as a starting point, not a permanent artifact.

The Bottom Line

Modern controls are improving, but platform updates can change behavior and appearance without warning. When the combobox acts or looks different:

1. Confirm you're on the modern control and that SelectMultiple and DisplayMode match your intent.
2. Add a Reset button as a reliable fallback for clearing selections.
3. Set appearance properties explicitly if you need consistency across rollouts.
4. Use Microsoft Learn as the source of truth—the docs are updated with each release.

Your app should serve the people using it. When the platform shifts, a small set of explicit choices (Reset, Appearance, SelectMultiple) keeps you in control.

Sources and Further Reading

• Combo box modern control in canvas apps
• Modern controls overview
• Power Apps Community Forum – Power Apps