If you click on the whitespace in a map and drag, the map pans. If you click without dragging, the map scrolls the focused node into view. This latter behavior is functionally expressive, but it's inconsistent and can be frustrating if you are browsing a large map and accidentally click without dragging. An example of where this is easy to do is if you click in the FreeMind window to refocus it after working in another application.
The least controversial change would be to make this behavior customizable either in the UI or at least as a Java property.
However, it may be worth considering disabling it by default or only activating it on double-click. Changing default behavior is hard because there's always a risk of upsetting someone, but for my part I've rarely found the behavior to be welcome.