You can achieve this by following these steps:
1. Start by creating a collection to store your choices. You can do this in the OnVisible or OnStart event of your app using the ClearCollect function:
ClearCollect(colChoices, ["New", "In Progress", "Cancel", "Resolved"])
2. Next, add your collection to the Items property of your ComboBox control.

3. Enable the "Allow Searching" option on your ComboBox.
4. Create a button or icon that allows users to add a manual choice. Configure the OnSelect property of the button as follows
Collect(colChoices, ComboBox1.SearchText);
Reset([@ComboBox1]) //Clears out searchText so user knows they need to reselect
With these steps completed, you'll have a finished demo:
1. When a user clicks the drop-down and starts typing a manual choice, they can then click the button to add their choice.

2. The manually added choice will be included in the drop-down list for selection.

This setup allows users to dynamically add choices to the ComboBox, providing flexibility and customization in your app.
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Cheers!
Rick Hurt