This is a feature that would be nice to add, since it's time consuming to hide the layers you don't want merged, then manually merge the visible ones. Why not have a simple option that merges all the layers that are visible?

This already exists, just in two steps. First select all visible layers with Layer->Select->Visible layers, then use Merge with layer below.

slangkamp wrote:This already exists, just in two steps. First select all visible layers with Layer->Select->Visible layers, then use Merge with layer below.

That doesn't work if you do the selection manually and/or use the keyboard shortcut for merging layers. This should be a no brainer that didn't require stepping through menus.

As an update, there's no 'select visible layers' option anywhere on 2.9.11

That's because it's in 3.0 pre-alpha. You can hotkey it even.