This can occur often when you are using ProjectWise projects (indicated by the special folder icon in PW Explorer)
One feature of using these projects is to allow you to limit which resources (Application, Department, Environment, Storage, View, Workflow, Workspace Profile, Component Custom Folders, Rendition Profile) are available, however you may need to add/remove a resource if project requirements change. You can configure what resources are available within that project, in the properties - resources tab, and have the option to specify which ones are available, or configure to inherit from its parent project or directly from the datasource settings.
For example, I added a new workflow in the ProjectWise Administrator, named "New Workflow"
However, it is not available in this folder
To make it available under the BSI200 project, go to the project properties-resources tab and note the workflow is set to Locally Assigned, and does not include "New Workflow". Click Add to select the specific workflow, or Inherit which will show every workflow in the datasource (as well as any that may be added in the future)
The new workflow is now available to use in folders under the BSI200 project