Delete a resource
In the Resources panel, right-click the resource that you want to delete.
From the drop-down list that appears, click Delete.
The XAML for the resource is deleted from your document. If there are any objects that still reference the deleted resource, a popup window appears, listing the objects. In this window, you can choose from the following actions:
Update the affected properties to reflect the new resource name.
Convert the property to a local string value.
Reset the properties to default values.
Choose not to fix the broken resource references.
In the Existing References Found window, if you choose not to fix anything, there will be build errors unless you create a new resource with the old name before you build your application.