I am not sure about the extension... I haven't used it for years, and I always found it slow...
But you can pull up Activity Map data into Workspaces which gives you a lot more control if you are haven't trouble with the actual extension.
If you search in your components panel in workspace for "Activity Map", you should see the following dimensions:
- Activity Map Page
- Activity Map Link
- Activity Map Region
- Activity Map Link by Region
As well as instances for each of the above...
If you want to limit the a specific page, you can segment for Activity Map page = X
Then you can pull up "Activity Map Link" or "Activity Map Region" etc.. I usually stick to the "Activity Map Link Instance" metric....