GridViewColumnGroup.HeaderTemplate is not respected in Windows8, Windows8Touch and ExpressionDark themes. Instead, the name of the column group is its content.

This is reproducible with both StyleManager and Implicit Styles.

Should be resolved with lib version 2015.2.720.

The problem can be reproduced only when the previously focused element is in ToolBar or RadToolBar. It is not reproducible in the default scenario. 

Should be resolved with lib version 2015.2.713.

А new virtualization mechanism for ColumnGroups will be introduced with Q2 2015. A property EnableColumnGroupsVirtualization is exposed with default value True for enabled virtualization. Setting it to False will enable the old logic.

The fix will be available with Q2 2015.

Just run the attached project and scroll horizontally to the very end several times (at least two times).
I tried disabling the column virtualization but this did not help.

This issue will be resolved with Q2 2015. 
A new virtualization mechanism for ColumnGroups will be introduced with Q2 2015. A property EnableColumnGroupsVirtualization is exposed with default value True for enabled virtualization. Setting it to False will enable the old logic. 

This problem is reproducible only in WPF and can be observed on both Row Context Menu and Header Context Menu QSF examples.

The fix will be available with Q2 2015 version.

Focus stops moving but selection keeps moving when navigating through the keyboard down key. When the window is stretched so that the ScrollBar is not visible, the issue could not be reproduced.

GridViewDataColumn.IsVisible binding is broken in a custom scenario. The problem is reproducible only in child GridView.

It should be resolved with lib version 2015.1.504.

When you place a DataTrigger whithin a CellTemplate, it is being ignored by RadGridView for WPF

Workaround ( until fixed ) - set the ContentTemplate of the cell via Style in a static resource instead.

The issue is reproducible with Q1 2015 SP1 version. With Q1 2015 it is not.
In order to reproduce it, add at least one empty cell. When you try opening the excel file you get the an error that Excel will try to recover the file.

Should be resolved with LIB version 2015.1.413.