Using Resource Dictionaries in a Class Library - wpf

Question

I'm using this (excellent) flowchart diagram designer in my application, but I'd like to use it as a UserControl.
To convert the Application into a UserControl I've changed the only window the application had:
<Window x:Class="DiagramDesigner.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:s="clr-namespace:DiagramDesigner"
xmlns:c="clr-namespace:DiagramDesigner.Controls"
WindowStartupLocation="CenterScreen"
Title="Diagram Designer"
Height="850" Width="1000">
<Window.Resources>
<ContextMenu x:Key="DesignerCanvasContextMenu">
...
</ContextMenu>
</Window.Resources>
...
</Window>
into an user control:
<UserControl x:Class="DiagramDesigner.DiagramDesignerWPFControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:s="clr-namespace:DiagramDesigner"
xmlns:c="clr-namespace:DiagramDesigner.Controls"
Height="850" Width="1000">
<UserControl.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
...
</ResourceDictionary.MergedDictionaries>
<ContextMenu x:Key="DesignerCanvasContextMenu">
...
</ContextMenu>
</ResourceDictionary>
</UserControl.Resources>
...
</UserControl>
I took the ResourceDicctionary from the contents of App.xaml and added it to the control. Then I deleted the App.xaml file, as it can't be used in Class Library compilations.
My problem is:
When I add that new User Control to a WPF Form in another project, I can run the new application, I can add chart components and move them, but when I join/link the following exception raises:
Cannot find resource named '{SolidBorderBrush}'. Resource names are case sensitive.
What am I doing wrong with the resources or their location in my User Control?
Edition after accepting the answer:
The risen exception also pointed to a line where the '{SolidBorderBrush}' was called. I didn't initially put it in this question, as it was a call and not a declaration. This is the piece of code which linked the exception:
<Trigger Property="IsMouseOver" Value="true">
<Setter TargetName="Border" Property="Background" Value="{DynamicResource ToolbarSelectedBackgroundBrush}" />
<Setter TargetName="Border" Property="BorderBrush" Value="{DynamicResource SolidBorderBrush}" />
</Trigger>

Answer 1

Im guessing here, because your question doesn't actually show any of the code which seems to be causing the issue, but you probably need to use DynamicResource.
{DynamicResource SolidBorderBrush}
You can only use StaticResource under very particular circumstances. You get a big performance boost most of the time, but it's very easy to end up in a situation where it can't be used (which may be what has happened).