I really enjoy this tool and I've found the forum to be very helpful as well. As a feature request, I thought I might suggest the following:
1. It would be really neat to be able to have multiple central ideas, especially for larger maps. Right now I am planning a writing project and I think that the ability to have multiple maps side-by-side (but not necessarily having the same central idea) would make the overall map appear cleaner and also give more flexibility in creation
2. It would also be really cool to be able to select multiple nodes or thought bubbles and add the same formatting changes (for example, give them a red border instead of a blue border). Currently, they have to be selected one by one to apply these changes.
Thanks again for your work on this beautiful tool!