Gimp 3.0.2- Problem merging down layers

[Mel987]

Hi! I need to emerge some layers, but when I try to do so the program erases one of them instead of emerging them (if I use emerge down) or most of them (If I try to add my layers to a group to emerge it as a whole, most of them become invisible before I even try to emerge them), and I don't know why. This problem only presents with one file so I don't think it's a problem with my Gimp or its configuration, but I've been only working with Gimp for a few months, so I don't know much about the program or how to solve this problem. Thanks for the help!

(Please forgive any grammatical errors, English isn't my first language)

[Ofnuts]

This is because the effect of a layer blend mode is by default constrained to the group the layer is in (think of groups as parentheses in a formula).

In this image:

   

The green disk in Addition mode only acts on the red disk (*) because its influence/scope is constrained to the group.

If you change the Group to Pass through, it is no longer constraining the scope of its layers, and the green disk Addition mode is also applied to the background layer:

   

So you get the same image as if the layers where outside groups:

   

So, you immediate problem is solved by putting the group in Pass through mode, but this may come back and bite you later, because the Normal behavior is there for fairly good reasons 

(*) because outside of Normal mode layers only act on the opaque part of the layer stack below them.

[Mel987]

(5 hours ago)Ofnuts Wrote: This is because the effect of a layer blend mode is by default constrained to the group the layer is in (think of groups as parentheses in a formula).

Thanks a lot for the whole explanation! It was very complete and easy to understand