Unlike other related tools (e.g. ChallengeEdit) this tool writes data back to the file from nothing and does not save file "positions". Basically this allows things like block adding, removing, renaming etc. straight from inside the application.
Besides, it is able to display some additional information about your map.
Anyway, some screenshots.



A short guide on how to get started quickly.
1. File -> Open your map
2. Select a block, at the right hand side modify it's values (modifying positions is easiest). Hit apply when you're done.
3. File -> Save your map
Note: Back your map up regulary when using this tool (also if you do not use it, by the way). I can not garantuee that it always works, even though I've tested it a lot.
Download
Binaries (The application itself) - v3
For TMT: Binaries
Source code
Changes
1. v1 (minor) - Fixed the crash when a map is opened with music.
2. v1 (minor) - Fixed a crash when the block list view should reload without a map loaded. Added shortcuts.
3. v2 - Updated to Qt 5.3.2, fixed parser bugs regarding unassigned blocks (affecting especially Valley), added new classes used in newer Maniaplanet updates allowing new maps to be loaded too, added toggle for ghostblock-value.
4. v3 - Special blocks/clips listing, ground variant checkbox, hex flags input.
Future
This application is not yet fully completed, but so far it allows blockmixing in any title/environment. In the future I plan adding ways to edit other data stored in the gbx file, like modifying custom objects' positions etc.
If you feel like contributing to the application, you can do so through Github (see the source code link).
Enjoy
