The title needs to be more specific, "GIMP tutorial" has no meaning for me, as it is already a sub-forum.
The right click on a layer while a GEGL or any filter with "preview" is open to have a "New from Visible" is more in description line with the title (yes beginners need to know about it, and that's nice that someone finally speaks about it).
But yeah the title of your post should be something like "New from Visible while a filter with preview is open", thus there is NO hidden image => check the split the view option and you will got a spited view from "new from visible" (using it often I can say I know it well => it's just a "new from visible" which should be in the title, no hidden image)
The right click on a layer while a GEGL or any filter with "preview" is open to have a "New from Visible" is more in description line with the title (yes beginners need to know about it, and that's nice that someone finally speaks about it).
But yeah the title of your post should be something like "New from Visible while a filter with preview is open", thus there is NO hidden image => check the split the view option and you will got a spited view from "new from visible" (using it often I can say I know it well => it's just a "new from visible" which should be in the title, no hidden image)
Patrice