Version 2016.3.1024.45 (from nuget packages, if that matters)
Adding a new row with the "Add new row" button and then clicking the row indicator results in an extra row. Demo: http://recordit.co/Nn8y2z2YpI

Available in the R1 2017 SP1 Release.

Using SearchPanel and getting search results highlighted is a very usefull feature. However at the moment it is only possible to change the color of the highlight-portion of HighlightTextBlock. It would be nice if I have more formatting options like:

• HighlightFontWeight
• HighlightFontStyle

etc. So if I search for "find" I get results like "find me"

this is not related only to grid-inside-grid scenario (HierarchyChildTemplate), but also for a flat (classic) grid control. If you have a GridView and any other control (ex TextBox), you will notice that if you move focus from GridViewCell to TextBox, both

There are cells exported for the group rows, but they are empty. If you define ColumnGroupDescriptors instead GroupDescriptors, then the exported data is the correct one.

Border is not correct when FilterRow is on and Column header is wrapped. Sample and Screenshot attached.

The group panel item image of a column with custom header is blurred

Enhance aggregate functions (like Sum) in footers so they support expression columns in RadGridView. 

See the attached project. It works for DataColumn, but raises an exception that no suitable generic Sum method could be found when I set the Sum footer for an expression column.

When you define a style targeted at GridViewCell with a color without transparency, horizontal grid lines are hidden.

The RowStyleSelector is great for dynamically styling rows, but there doesn't seem to be an easy way to dynamically apply a style to selected rows - they just take on the default style. Something like a SelectedRowStyleSelector would be a great way to dynamically style selected rows. Thanks!

Added the CanUserSearchInHiddenColumns property which indicates whether users can search for content in hidden columns. The property is available with our 2017.3.1127 internal build.

Sample:
<telerik:RadGridView ShowSearchPanel="true" ShowSearchPanelCloseButton="false"
or
<telerik:RadGridView ShowSearchPanel="true" ShowSearchPanelCloseButton="Hidden"