By default, TagEditor wraps the items within the control as the number of items increases. However, you can change it's behavior and disable the wrapping of tags by setting TagWrapping property of the C1TagEditor class to false.

This is how the TagEditor control looks when the items are wrapped and without wrapping.

To disable item wrapping in TagEditor, you can use the following code:

<c1:C1TagEditor Name="te" TagWrapping="False" HorizontalAlignment="Left" VerticalAlignment="Top" Width="280" Margin="10"/>

C1TagEditor te = new C1TagEditor();
te.TagWrapping = false;