Error migrating VisualStudio shell from 14.0 to 15.0, VsBrushes can not be found

Hi,

I am trying to upgrade all the extensions for my project and the project as well. When I install extension from Microsoft.VisualStudio.Shell.14.0 to Microsoft.VisualStudio.Shell.15.0, I get the following build error. All this is in a xaml file

"cannot find the type VsBrushes, note that type names are case sensitive"

The source of the issue is:

<Border Background="{DynamicResource {x:Static shell:VsBrushes.CommandBarOptionsBackgroundKey}}"
TextElement.Foreground="{DynamicResource {x:Static shell:VsBrushes.CommandBarTextActiveKey}}"
BorderBrush="{DynamicResource {x:Static shell:VsBrushes.DropDownBorderKey}}"
BorderThickness="1">
<Grid>

When I install Microsoft.VisualStudio.Shell.14.0 extension, This works but many things fail. I actually did code to use 15.0 instead of 14.0 in the same page. As:

xmlns:shell="clr-namespace:Microsoft.VisualStudio.Shell;assembly=Microsoft.VisualStudio.Shell.15.0"

 Is there any way to get this thing run using 15.0 by finding VsBrushes. Any help is appreciated.

Luc