Where is revision history and comments?

With our team we often collaborate on mindmaps. Recently we have moved to SharePoint, and we're trying to integrate MindManager better with it. One of the features that would really make collaborations a lot easier is version history and version comments.

MindManager seems to support that for files saved on SharePoint. When saving a file and checking it in, MindManager asks if you want to write down a version comment. However, afterwards, those comments are nowhere to be found. The manual speaks of a 'Revision pane', but I can't seem to find or enable that in my pane.

Any help with this issue, or general tips on collaboration, would be greatly appreciated. Thanks a lot!