In the current CollectionView implementation, the CollectionView will start with all the groups expanded. The only way to have any form of preference is to programmatically interact with the DataView after-the-fact https://docs.telerik.com/devtools/maui/controls/collectionview/grouping/expand-collapse

Add an option to scroll fast to elements inside the CollectionView, something like jump list approach.

This feature is available in the iOS UICollectionView https://developer.apple.com/documentation/uikit/uicollectionviewdatasource/2851455-indextitlesforcollectionview

It could be a great addition to the Telerik MAUI RadCollectionView features set.

Provide support for right-to-left flow direction: 

The current behavior is that the items

when the device language is set to an RTL language (like Hebrew or Arabic) causing the FlowDirection to be set to RightToLeft, where UI will show correctly with RTL FlowDirection, but the item's corresponding tap areas are still in the LTR positions. 

In MAUI CollectionView when scrolling an item into view, the exact position of the item after the scroll has completed can be specified with the position argument of the ScrollTo methods.

Please provide such option for Telerik MAUI CollectionView inside the ScrollItemIntoView method.

Currently, the LoadOnDemandCollection accepts a callback of the following format in the constructor:

public LoadOnDemandCollection(Func<CancellationToken, IEnumerable> action)

It is a very common scenario to populate the items asynchronously. In its current form the collection would require blocking the current thread to populate the results:

ItemsSource = new LoadOnDemandCollection((cancelationToken) =>
{
    var result = new List<ItemsModel>();
    try
    {
        var items = dataService.GetItemsAsync().Result;

        // TODO: Handle the result.

        return result;
    }
    catch (Exception e)
    {
        // TODO: Handle the exception.
        return null;
    }
});

This is not desired, as using Task.Result blocks the current thread and is considered an anti-pattern, in general.

A better approach would be to add a second overload of the constructor, allowing asynchronous calls:

public LoadOnDemandCollection(Func<CancellationToken, Task<IEnumerable>> action)

This way we can use async and await in the callback instead:

ItemsSource = new LoadOnDemandCollection(async (cancelationToken) =>
{
    var result = new List<ItemsModel>();
    try
    {
        var items = await dataService.GetItemsAsync();

        // TODO: Handle the result.

        return result;
    }
    catch (Exception e)
    {
        // TODO: Handle the exception.
        return null;
    }
});

According to my tests, the first blocking approach is not a problem, as the LoadOnDemandCollection starts a thread internally. That behavior is not obvious however, and using Task.Result is somewhat counterintuitive, so the second approach is much better from the user's perspective.

Currently the group descriptors provide a SortOrder property, so the groups are sorted alphabetically in descending or ascending order.  We would need to cover the following scenarios:

- allow certain groups to be ordered at the top, possibly by specifying an comparer or a separate group sort property.

- show the groups in order the corresponding items appear in the ItemsSource.

The ItemsSource of the views is populated in the ViewModel of the page. This is done in a command that is triggered by the NavigatedTo event of the page, which is forwarded via EventToCommandBehavior from the Maui Toolkit.

When using the RadCollectionView the loaded items are no longer displayed. 

When the ObservableCollection of the items is completely reconstructed and reassigned the display works.

Provide a built it way to notify the parent group when the items in the nested groups are changed. 

For example, there is no PropertyChanged or CollectionChanged notification that we can hook in to in order to detect updates in parent group headers when the count changes in a subgroup. Only the leaf group headers get updated, but not the parents.