Mobius Map Editor - Map Size

[Dasha]

Hi,

In the past years, I created few maps for OpenRA but recently decided to go back to the real Red Alert.

These are the maps I created : https://resource.openra.net/maps/uploader/Dasha/ 

I've seen that the most recent editor is Mobius (which looks very user friendly) but to start with, I've not found how to adjust the map size. By default, it seems to be 126x126 and I've not been able to change this settings.

Anyone knows how it can be adjusted ?

D