Changes
/* DataTrigger permanently blocks manual changes {{Version/MobileSince|5.0.0}} */
In the example below a DataTrigger is used to set the selected tab based on the record's metaclass. The initial selection works correctly, but afterwards the user can never manually switch to a different tab. Tapping another tab header highlights it, but the content never switches, and SelectedIndex silently reverts.
{| class="wikitable" style="width:100%; table-layout:fixed;"
|}
{{Attention|This is not limited to tab selection. The same problem can occur wherever a DataTrigger, Trigger, MultiTrigger sets a property that a user (or code-behind) is also meant to change afterwards, e.g.for example:}}* Selection controls: Picker.SelectedIndex/SelectedItem, CollectionView/ListView.SelectedItem, RadioButton.IsChecked, Shell.CurrentItem
* Toggle/input controls: Switch.IsToggled, CheckBox.IsChecked, Entry/Editor.Text
* Expand/collapse state on any control the user can also expand/collapse manually
* Code-behind writes executed after the trigger has already applied a value (not just touch input)
{{Hint|When converting Use a DataChangedBehavior with SetPropertyAction instead of a Xamarin DataTrigger, if the property it sets should remain user-changeable afterwards, convert it into a DataChangedBehavior with SetPropertyAction. Keep DataTrigger/Style.Triggers only for properties that should stay continuously data-driven and don't conflict with user input.}}
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