Box select is broken for all node editors. It ignores selection modes and always uses the mode `Set a new selection`. The operator `NODE_OT_select_box` works fine, but clicking anywhere in the node editor calls `NODE_OT_select` first, so we need to make sure it has no undesired side effects when it is not run. Pull Request: https://projects.blender.org/blender/blender/pulls/133736