I made corrections and added new possibilities.
The first tab 'View' display image icons.
The second 'Zoom' displays the original image in the client area (Sorry Timo I don't append to make a real zoom).
The third 'Effect' lets you see what appends when applying an effect.
The fourth 'Memory' is cumulative. It adds all the effects for the current image file. Sometimes it is very fun.
The fifth 'Layers' is a bit complicated (for me) : You have colors, textures, fusion mode, and 3 sources (Original, Effect and Memory).
You combine them while appliying first the color and the color with then this result with the source always using the fusion mode.
Strange sometimes but funny too.
You can donwnload the program
here.
Please send me comments, the test are not finished, I always try to find bugs but I am alone.