How can I prevent layer effects from overwriting when merging layers?
Often when I apply some effects to layers, and I merge them, the ones with effects have their blending mode messed up. They act as if all of their layer blending mode became normal and then merged. But I think sometimes it doesn't happen.
What can I do to prevent this?
Select both layers from layers panel with Shift and then hit Ctrl + E to merge them. Your effects will not change.