For the patches, they are available here : http://scrapbookcampus.com/resources/psp-patches/
For the thumbnails, check the Thumbnail Handler in the Utility section here: http://scrapbookcampus.com/resources/
when you open a file with several layers, and wish to amend one layer, you can no longer see the full picture and assess the overall effect, only the layer at hand is visible.
I am not sure what you mean here as I always see the “end result” of all the layers together. Would you mind explaining or adding a screenshot of what you are looking for?
