If i have set thumbnails as the view mode (Set VIEW=Thumbnails), then set columnstoggle=thumbnail(0)
doesn´t work, while it works alright from all other modes.
What are you expecting it to do?
There are no columns in Thumbnails mode so trying to toggle a column in that mode doesn't make sense to me.
The aim was, to toggle between regular thumbnails & the new, mixed mode, containing thumbnails. But your answer explains,
why it doesn't work.
You'd have to make the command switch to Details or Power mode, then add the column.
Thanks, that works 
. Here is, how i can toggle it back to thumbnails view:
set View=details,thumbnails,cycle columnstoggle=thumbnail(0)