Ability to "save as"/"open" and use Freemind format instead of .mup
I have several kinds of maps on various environments and operating systems, private and at work. What connects them is the Freemind format. Instead of exporting my .mup to .mm, it would be great to have the choice, which format I want to use for my work.
This would be better than export/import, because it would remain only ONE map. An export creates a new map, so I can't work on my original map for improvements, if I have to use another tool. Afterwards I have to reimport all the changes manually into my orininal .mup or create another "new" map be simply importing the .mm. So this workflow creates a lot of maps and I'm busier with managing my maps and map formats, than with using the tools.
As Freemind is a de facto standard for many, that would be a great improvement, even if it had less functions compared to the .mup format in the beginning.