There are types when PCEs cannot be used, or when it makes more sense to use SFx assignments to manipulate parameter controllers. When a note event which contains an SFx command is right-clicked, there should be a couple of extra submenus available for easier assignments, similar to the PCE contextual submenus in the Pattern editor.
When right-clicking on a note event with an SFx command, a contextual menu would open which gives extra options for re-assigning the control, allowing the user to not have to open the Macro manager window just for one re-assignment. In all cases, the Macro type would be selectable from a submenu (such as Control Plugin param, MIDI CC, etc.)
If no instrument is assigned in the SFx note event AND the macro type is for plugin control, one submenu would allow for choosing the plugin to control.
If an instrument IS assigned in the note event and the macro type is for plugin control, then another submenu would allow for the parameter to control.