We would like to have the ability to merge cells vertically with same content. Consider to do the same horizontally.

Especiall for wide lists it would be very helpful to be able to zoom in and out of a RadGridView, in order to see more or less columns. 

Also see: http://www.telerik.com/forums/scaling-of-radgridview-content

When using Search as You Type behavior, the items will be first filtered using the keywords typed in the TextBox. We can create a way to disable this filtering.

Show a tooltip when text exceeds column width.

Available in the 2017 R1 Release (2017.1.117).

As of R1 2018 RadGridView supports pinning columns both on its left and right side. The new properties that control the right-side behavior are: RightFrozenColumnCount and RightFrozenColumnsSplitterVisibility.

Currently I am using row selection for my readonly grid. There is a cell highlight that shows which cell the user has selected.  I would like to disable that highlight so that the row selection looks consistent no matter where on the row the user clicks.
(Copied from: 
http://www.telerik.com/forums/disable-selected-cell-highlight

See this link for more details:  http://www.telerik.com/forums/how-to-remove-focus-rectangle-from-selected-cell#9GAEx-HPN0C_qOGAsXY2PA   )

This should be possible without adding 200 lines xaml code. Just expose the CellBorderBrush Property so we can easily set it to transparent

Add an ability for the user to select a full column (the SelectionUnit should be Cell and the SelectionMode should be Multiple or Extended). 

Consider this behavior in regard with the sorting of the column.

We could add an option to group the dates in the FilteringControl similar to how Excel groups them.

Provide option to enable changing the column display index when dragging group cell into the header row.

Available in the 2017 R1 Release (2017.1.117).

The exception message is: "... is not a valid metadata type for type filtering operations. Type filtering is only valid on entity types and complex types." The exception is observed when using AggregateFunctions and setting up the data with EntityFramework. 

Introduce a way to set the modifier key used for multi-column sorting.

Available in LIB version 2016.3.1128, it will be also available in the 2017 R1 Release.

The problem occurs from 2014 Q2.  It should be resolved with lib version 2014.3.1319.