Change the Default Selected Filter Operator:
https://docs.telerik.com/devtools/wpf/controls/radgridview/filtering/how-to/howto-change-the-default-selected-filter-operator

This doesn't work for boolean columns, if the property "ShouldGenerateFieldFilterEditors" of the column is set to "True". 

Please see the attached example.

*** The fix for this issue will be available with the next LIB (version 2018.3.1217) expected on Monday, December 17.

To reproduce this:

1. Set the ShowToolTipOnTrimmedText property of RadGridView to True.
2. Hover a cell with trimmed text.
3. Before the tooltip shows, move the mouse quickly, outside of the RadGridView control.
4. Regardless of the fact that the mouse cursor is outside of the RadGridView control, the tooltip showing is not canceled and it shows after a second.

To resolve this, set the ShowToolTipOnTrimmedText of the gridview columns instead of the RadGridView control.

for radgridview,if CanUserFreezeColumns="True" ,
when adjust the FreezeColumnsResizer to the right,and then resize the left colum'width,
if exceed the visual area,these exceed area's column will disappear!
for example,the data virtualization sample for the radgridview,if set the FreezeColumnsResizer
to the 'Unit_Price' column behind,then adjust the 'Product_ID' column width to exceed the visual area,
at last by scroll,you can't find the exceed visual area columns

 Group rows which are not present in the view are not visualized when the window is maximized.

A possible solution here is to set the GroupRenderMode property to Flat.

This behavior is observed when Office2013 theme is applied. 

If your data contains uint, long or any numeric type different than Int32 or Decimal, the searching doesn't work.

Nested property definitions are visible in situations when they don't match the filtering criteria.

The following exception is observed in certain cases:

at Telerik.Windows.Controls.GridView.GridViewVirtualizingPanel.FlatLayoutStrategy.RealizeMergedCells(Double frozenOffset, IEnumerable`1 mergedCells)

at Telerik.Windows.Controls.GridView.GridViewVirtualizingPanel.FlatLayoutStrategy.CalculateMergedCells(Boolean shouldInvalidateMeasure)

at Telerik.Windows.Controls.GridView.GridViewVirtualizingPanel.CalculateMergedCells(Boolean shouldInvalidateMeasure)

at Telerik.Windows.Controls.GridView.GridViewCellsPanel.ArrangeOverride(Size finalSize)

In multiple selection mode, the GridViewMutiColumnComboBox column does not respect its DisplayMemberPath property.

 

When the new value is selected from the GridViewMultiColumnComboBoxColumn, the event arguments in the CellEditEnded event does not contain the new value. 

Currently the string is localized as "Filtre" and it should be localized as "Filtrer".

Add property to control whether the filtering dropdowns stay open.

When there are items with longer text than the FilteringControl's default width, the FilteringControl resizes when scrolling to these items. This behavior is observed with all themes, different from Windows 8 and Windows 8 Touch.

In some themes the arrow points up and in other themes the arrow points down. We should make sure that this behavior is consistent across themes. 

Clicking on the hyperlink does not open the link in .Net Core.

The background of the cells is exported when the ExportDefaultStyles property of the GridViewSpreadStreamExportOptions to False.

When you have rows grouped by null value and you try to move one of the rows to another group, a NullReferenceException is thrown.

This is reproducible only when DataView is used as ItemsSource of RadGridView.

To work this around, avoid using null values. Or avoid using DataView.

When sorting a grouped RadGridView, the selection is lost. 

When there isn't a vertical scrollbar visible, while performing a drag selection, empty rows appear.