If the DisplayIndex of the columns is set when they are initialized, ColumnGroups are not displayed.

As a workaround, you can set the DisplayIndex after the columns are initialized. 

 

The GridViewSelectColumn is a very nice and useful feature, especially the possibility to select all items with just one click on the header. It would be great if there was the same functionality for the group header. So clicking on a checkbox in group header will select all items in this group (only). I know there are some examples (many years old) of how to do this, but it would be much better if it worked out-of-the-box.

You are able to resize columns using the columns gripper. The corresponding group will be automatically resized. We can provide a way to resize the column groups. The columns inside the group will be automatically resized with the group.

The issue reproduces in the following situation.

• The selection mode is Extended and the selection unit is Mixed.
  
• Multiple rows are selected.
  
• Cells of the selected rows are updated.
  
• The column of the updated cells is previously sorted (before the update of the cell values).
  
• DataTable is used to populate the RadGridView control.

To work this around set the SelectionUnit property of RadGridView to FullRow or use a collection type like ObservableCollection<T> instead of a DataTable.

The row arrangement is implemented correctly, but because of rounding errors, gaps and rows overlapping may appear during the WPF render phrase. This happens if the boundaries of the row containers use too high precision for its values (top, left, bottom, right). Consider improving this by rounding the boundary values before calling the Arrange() method of the row's container.

In this case, the business object has properties with similar names "A" and "a". The default binding does not respect upper and lower cases for similar naming.

For example, we can create the SUM() function for the cells in the ViewPort.

Setting the IsVisible property of a column, which is frozen on the right size by setting the RightFrozenColumnCount property, does not work as intended. 

In Example 1 from Edit an item outside RadGridView article, we are suggesting to replace an item to trigger collection changed. This way the sorted/filtered collection will be updated. In this case, we are replacing the item with the same one. This will lose the selection after replacing it several times.

In this case, all columns have fixed width. Resizing one of the right frozen columns is not working as expected.

RadGridView provides two methods to bring an item into the view. We could extend these or create a new one to bring an item to a specific position.

At this moment, the Search As You Type functionality can be customized. We can expose several methods so that the user can override the default search behavior and implement their own.

Currently, you can navigate through the items in the distinct values list using the arrow keys. This changes the focused item. If you want to check/uncheck the currently focused item you need to press Tab in order to move the focus from the content presenter of the ListBoxItem to the CheckBox control.

Allow check/uncheck of the currently focused item using the keyboard (by pressing the Enter or Space key).

When column virtualization is enabled and there are columns with their IsVisible property set to False, resizing the right-most column can result in other columns being resized involuntarily.

Disabling column virtualization by setting the EnableColumnVirtualization property to False can be used as a workaround for the time being.

When resizing a column, it can cause it to become null and a NullReferenceException will be thrown.

Can be observed in FirstLook demo of the RadGridView.
While resizing the demos window, radgridview's horizontal scrollbar might flicker when demos viewport size is close to the gridview size.

Opening the filter control of the RadGridView control with Xaml binaries in certain themes will throw the following exception:

​System.Windows.Markup.XamlParseException: 'Provide value on 'System.Windows.Markup.StaticResourceHolder' threw an exception.'
Exception: Cannot find resource named 'NullToVisibilityConverter'. Resource names are case-sensitive.

An empty row appears when using grouping and the EnableStickyGroupHeaders="True", and the RowHeight property is set to a value bigger than the default row height (which is usually 25px, but it may vary based on the applied theme).

Search As You Type Text-Highlighting is does not work with dynamic objects.

Exception when changing ItemsSource when it's a CollectionViewSource and grouping is applied.