Our Silverlight Studio bundle contains a custom ToolBar control in the Shared Library, along with Menu and ContextMenu controls.
Here is how it looks in the default Aero theme, although the current official release doesn’t yet have the overflow button at the end. That is a new feature that has been added for the next maintenance release. Basically the overflow button is disabled unless there isn’t enough space to display all of the child controls.
In that case the overflow button can be clicked to display a popup that contains all of the child controls that weren’t able to fit on the main toolbar. The Office black-themed screenshot above shows the overflow popup.
In addition, we’ve added vertical orientation capabilities as seen in the Office blue-themed screenshot above. By setting the new Orientation property to Vertical, the toolbar renders vertically and even auto-rotates the background/border brushes and padding for you.
These new features will be in the next maintenance release of Silverlight Studio.