I would like to edit sections, to create (transparent) mask in each section.
I was able to edit upper left corner, but I cannot get to the next section
Yes... I was clicking on them... but it didnt work for me...
you have to hold the STRG-Key and move to the field you want to edit with the Arrow-Keys. Its a bit tricky and you often have to deselect the hole object, e.g. the pop-up window, reselect it and edit a new section, after you changed one section, since it locks itself up.
Hope this helps