The "delete this F-Curve" function assumes that the F-Curve is either a driver or contained in `adt->action`. This does not have to be true, as the Action editor can also show F-Curves from other uses (for example an NLA strip). The channel delete operator (`ANIM_OT_channels_delete`) now takes this into account. Pull Request: https://projects.blender.org/blender/blender/pulls/140291