Office 365 Users Only: NodeXL Graph Pane (“Document Actions”) does not appear

Symptom:

NodeXL successfully starts up (NodeXL Pro menu is present in the ribbon), but “Document Actions” does not load.

Solution:

For Microsoft Office 365 Users who find that the NodeXL Pro Graph Pane does not display, please follow these steps to activate the “Document Actions” pane:

Open Excel
Go to File->Options
In the “General” tab, under “User interface options”, select the second option “Optimize for compatibility”
Close Excel
Open NodeXL

For more details please refer to this URL: https://support.office.com/en-us/article/outlook-attachment-preview-failure-88020c8e-43ae-4582-9554-511fbaf0d138