When working in Windows with multiple monitors that have different display scales - dragging a window that contains a DataGrid with frozen columns would often lead to the frozen columns not getting rendered correctly. The frozen columns seem to not take into account the Dpi of the new monitor, but of the old one.

A scenario with a requirement to display information about the entire group, including recursively all child groups, needs access to the actual items and/or subgroups. Exposing these and parent info would allow for greater flexibility in displaying custom information in group headers.

I see iOS crashes in Sentry, seems like caused by clearing the RadCollectionView bound DataSource ObservableCollection, when an item was previously selected

Maui 9.0.70
Telerik 11.0

System.NullReferenceException: Arg_NullReferenceException
  ?, in void RadCollectionViewItemView.OnIsSelectedChanged()
  ?, in static RadCollectionViewItemView()+(BindableObject b, object o, object n) => { }
  ?, in void BindableObject.OnBindablePropertySet(BindableProperty property, object original, object value, bool didChange, bool willFirePropertyChanged)
  ?, in void Element.OnBindablePropertySet(BindableProperty property, object original, object value, bool changed, bool willFirePropertyChanged)
  ?, in void BindableObject.SetValueActual(BindableProperty property, BindablePropertyContext context, object value, bool currentlyApplying, SetValueFlags attributes, SetterSpecificity specificity, bool silent)
  ?, in void BindableObject.SetValueCore(BindableProperty property, object value, SetValueFlags attributes, SetValuePrivateFlags privateAttributes, SetterSpecificity specificity)
  ?, in void BindableObject.SetValue(BindableProperty property, object value)
  ?, in void RadCollectionViewItemView.set_IsSelected(bool value)
  ?, in void RadCollectionView.SelectContainers(IEnumerable items, bool select)
  ?, in void RadCollectionView.SelectionHelperSelectionChanged(object sender, RadSelectionChangedEventArgs e)
  ?, in void <>c__DisplayClass36_0.<SelectionChangerSelectionChanged>b__0(?)+() => { }
  ?, in void ActiveSelectionScope.Dispose()
  ?, in void SelectionHelper.ClearSelection()
  ?, in void RadCollectionView.Telerik.Maui.Controls.ICollectionView.ItemsChanged(NotifyCollectionChangedEventArgs e)
  ?, in void CollectionViewModel.OnDataProviderViewChanged(object sender, ViewChangedEventArgs e)
  ?, in void DataProviderBase.RaiseViewChanged(object sender, List<AddRemoveResult> changes, NotifyCollectionChangedEventArgs args, CollectionChange action, bool affectsAggregates)
  ?, in void LocalDataSourceProvider.ProcessCollectionChanged(NotifyCollectionChangedEventArgs e)
  ?, in void LocalDataSourceProvider.DataView_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void EnumerableDataSourceView.RaiseCollectionChanged(object sender, NotifyCollectionChangedEventArgs args)
  ?, in void EnumerableDataSourceView.ProcessCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void EnumerableDataSourceView.ProcessCollectionChangedOverride(object sender, NotifyCollectionChangedEventArgs args)
  ?, in void EnumerableDataSourceView.ProcessPendingCollectionChange()
  ?, in void DataProviderBase.RaiseViewChanging(object sender, IList changedItems, CollectionChange action)
  ?, in void LocalDataSourceProvider.DataView_CollectionChanging(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void EnumerableDataSourceView.HandleCollectionChangedOverride(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void EnumerableDataSourceView.Telerik.Maui.IWeakEventListener.ReceiveEvent(object sender, object args)
  ?, in void WeakEventHandlerList<NotifyCollectionChangedEventArgs>.ProcessEvent(object sender, object args)
  ?, in void WeakEventHandlerList<NotifyCollectionChangedEventArgs>.OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void ObservableCollection<ViewBundle>.OnCollectionChanged(NotifyCollectionChangedEventArgs)
  ?, in void ExtObservableCollection<ViewBundle>.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
  ?, in void ObservableCollection<ViewBundle>.OnCollectionReset()
  ?, in void ObservableCollection<ViewBundle>.ClearItems()
  ?, in void ExtObservableCollection<ViewBundle>.ClearItems()
  ?, in void Collection<ViewBundle>.Clear()
  ?, in void SearchViewViewModel.Dispose(bool disposing)
  ?, in void PropertyChangedNotifyingBase.Dispose()
  ?, in async void ViewBundle.Dispose(bool disposing)
  ?, in void <>c.<ThrowAsync>b__128_0(?)+(object state) => { }
  ?, in void NSAsyncSynchronizationContextDispatcher.Apply()
  ?, in void __Registrar_Callbacks__.callback_3311_Foundation_NSAsyncSynchronizationContextDispatcher_Apply(IntPtr pobj, IntPtr sel, IntPtr* exception_gchandle)

A NullReferenceException is thrown during the measure phase of a DataGridTextColumn when a CellRenderer is applied:

Object reference not set to an instance of an object.
   at Telerik.Maui.Controls.DataGrid.DataGridColumn.MeasureDrawingPaintable(LambdaPaintable lambdaPaintable, Object measureContext)
   at Telerik.Maui.Controls.SkiaSharp.SkiaLambdaPainter.Measure(MeasureablePaintable paintable, PurePainterContext context, Double widthConstraint, Double heightConstraint)
   at Telerik.Maui.Controls.DataGrid.MasterArranger.MeasureNodeContainer(Object container, Double widthConstraint)
   at Telerik.Maui.Controls.DataGrid.MasterArranger.MeasureNodeContainer(Object container, Double widthConstraint)
   at Telerik.Maui.Controls.DataGrid.MasterArranger.MeasureGridCellModel(GridCellModel model)
   at Telerik.Maui.Controls.DataGrid.CellModelGenerator.GetSize(GridCellModel decorator)
   at Telerik.Maui.Controls.DataGrid.CellsController`1.GenerateCellsForRow(IItemInfoNode rowModel, Int32 rowSlot)
   at Telerik.Maui.Controls.DataGrid.NodePool`2.GenerateModelsForInfos(IList`1 itemInfos, ModelGenerationContext modelGenerationContext, MeasureContext measureContext)
   at Telerik.Maui.Controls.DataGrid.NodePool`2.MeasureForward(MeasureContext& context)
   at Telerik.Maui.Controls.DataGrid.NodePool`2.MeasureVertically(RadSize availableSize, Double offset, Double verticalBuffer)
   at Telerik.Maui.Controls.DataGrid.NodePool`2.OnMeasure(RadSize availableSize, Double offset, Double verticalBuffer)
   at Telerik.Maui.Controls.DataGrid.GridModel.MeasureCells(RadSize availableSize)
   at Telerik.Maui.Controls.DataGrid.DataGridContentLayout.Measure(Double widthConstraint, Double heightConstraint)
   at Microsoft.Maui.Platform.MauiPanel.MeasureOverride(Size availableSize)
   at ABI.Microsoft.UI.Xaml.IFrameworkElementOverrides.Do_Abi_MeasureOverride_0(IntPtr thisPtr, Size availableSize, Size* result)

when setting a custom font to the column header style, the DataGrid crashes with null ref exception on WinUI.

Currently, the PropertyGroupDescriptor in the DataGrid component does not support grouping by nested properties (e.g., Customer.Address.City). Enhance the PropertyGroupDescriptor to support nested property paths, allowing developers to group data based on sub-properties within complex objects. This would align with common data-binding patterns and improve the flexibility of the DataGrid for real-world scenarios involving nested data models.

When the CollectionView is grouped and an element is removed from the source collection and inserted again immediately after that, it results in its parent group not expanding/collapsing when tapped. The tap is registered and the visual indicator of the group state is changed but the group is not actually collapsing and expanding. This issue is happening for groups with only one child item. When scrolling so the group gets our of the visible area and then scroll to the group again, the collapse/expand functionality works.

When a column in the DataGrid is being resized and is subsequently scrolled out of the viewport, a NullReferenceException is thrown. This happens because the column's model is recycled while the resize operation is still in progress. As a result, the resize logic attempts to access a column from a recycled (and now null) model, leading to the exception.

I would like to use a mouse to drag a row to a new spot in row order.

Found this info for WinForms, but not finding anything for MAUI RadDataGrid

https://docs.telerik.com/devtools/winforms/knowledge-base/gridview-drag-drop-bound-mode 

https://docs.telerik.com/devtools/winforms/controls/gridview/end-user-capabilities/reordering-rows 

An ArgumentException is thrown in the DataGrid when updating a property that exists only on a derived type of an object used in the grid's data source. This occurs specifically when a DelegateAggregateDescriptor is applied to a column.

When the client picks a random item from the ItemSource and changes the value of its property for which a GroupDescriptor is set, the CollectionView crashes.

when the developer does not have a license configured on their machine. Early on in the workflow of our app, the application will crash when we attempt to create a new PopupOverlay from an external dependency, such as the CommunityToolkit,

There is a memory leak in the TreeView on iOS/MacCatalyst - when the TreeView control is on the page, the page does not dispose when GC runs.

I have a user who reported a crash. In Sentry, I see this:

System.NullReferenceException: Object reference not set to an instance of an object.
  ?, in void TelerikLicense.ShowLicenseMessage(Page page)
  ?, in void TelerikLicense.VerifyLicense(Element element)+() => { }
  ?, in void TelerikLicense.ExecuteActionOnLoaded(Page page, Action action)
  ?, in void TelerikLicense.VerifyLicense(Element element)
  ?, in object <InitializeComponent>_anonXamlCDataTemplate_21.LoadDataTemplate()
  ?, in object ElementTemplate.CreateContent()
  ?, in void BindableLayoutController.CreateChildren()
  ?, in NotifyCollectionChangedAction NotifyCollectionChangedEventArgsExtensions.Apply(NotifyCollectionChangedEventArgs self, Action<object, int, bool> insert, Action<object, int> removeAt, Action reset)
  ?, in void BindableLayoutController.ItemsSourceCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void WeakNotifyCollectionChangedProxy.OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
  File "ObservableCollection.cs", line 192, in void ObservableCollection<T>.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
    handler(this, e);
  ?, in void ExtObservableCollection<T>.RaiseCollectionChanged()
the app was built with a successful license-check
Telerik.Licensing 1.6.6
 

When calling Focus() programmatically, the keyboard does not appear. 

When having a CollectionView and navigating between different views when tapping on an item from the CollectionView, the item(s) look(s) selected. 

It seems the behavior is due to the mouse over and selected visual states.

If you use FooterContentTemplate to add elements into the footer that require mouse over/click events (eg a Button or a Label with a tooltip), it works fine as long as the datagrid has enough data to scroll. However, if you resize the grid bigger or remove items until you no longer need to scroll and you have empty space between the last row and the footer, then none of those mouse events work.

When the value of a property used in a PropertyAggregateDescriptor changes, and the aggregate is displayed in the group header with GroupAggregatesAlignment="NextToHeader", the header does not reflect the updated aggregate result. This issue also occurs when RenderMode is set to SkiaSharp.

Provide a copyright label control for .NET MAUI. 

For example Telerik UI for WinForms introduced such control for the RadMap. For MAUI it could be nice to have such control in general

Please add support for multiple row column headers. As an example of what I'm referring to, see the Telerik UI for Blazor implementation here => Blazor DataGrid Demos - Multi-Column Headers | Telerik UI for Blazor