Why ?

The on-line editor is too limited: no code folding, no matching of { }, no global search...
How do you use your normal editor ?

How ?

My normal editor is ScITE, completed with regexxer for a global search . The operating system is Ubuntu . \

1 Export

The project name is RCCL. I export this as a RCCL.zip file in the MBED (/media/MBED for Ubuntu) . The reason why I export in the MBED is simple: the browser ask a confirmation for the download and it is the same destination for the compilet .bin file.

2 Mount

With fuse-zip I mount the zipped file as a filesystem.

fuse-zip /media/MBED/RCCL.zip /mnt/shared_lin/d/Develop/Mbed/Editor

All the program files are available in this folder .../Editor

3 ScITE

Normal use of this fine editor, opening a configuration file to open a list of programs in several tabs.

scite -cwd:/mnt/shared_lin/d/Develop/Mbed -loadsession:mbed.session

4 Unmount

After the close of the editor, the unmount is needed:

fusermount -u /mnt/shared_lin/d/Develop/Mbed/Editor

5 Import

Delete the program RCCL and Import the zipped file.

Conclusion

The simple corrections are better done with the online editor but for "big" changes the procedure described here is much better.
The needed software is available in Ubuntu (Synaptic Package Manager)