Please refer to the attached project that reproduces the issue. In the MainPage constructor, you can switch between using the PickerEditor (validation works) and the SegmentedEditor (validation doesn't work).
In Xamarin.Forms, there is no multiline text box editor in RadDataForm.
Currently, all groups are expanded by default. We should expose methods to collapse/expand certain groups. Furthermore, CollapseAll, ExpandAll groups should be considered as well.
Expose an IsEnabled property for editors that can be toggled after DataForm is rendered. Currently, only Data Annotations can determine whether or not a property's editor is read-only. If a specific editor's read only state needs to be changed dynamically (e.g. due to a selection in another editor), you would need to completely reload the DataForm.
The error message is not showing when the editor is empty and the ValidateAll method is called
Available in minor release 2018.2.727.250. It will also be available in the R3 2018 release.
Add FontFamily option to DataFormEditorStyle and DataFormGroupHeaderStyle.