I did not get that you were talking about Simulation Editor.
When you start using Blender, you will begin to try to master 3D View.
That is a menu present in header of 3D view, between Select menu and Object/Mesh menu.
Tooltip is showing its shortcut.
That is pretty obvious.
It is at same place, working the same way, in Node Editor.
Jacques Lucke just did not take time to create menus for header of Simulation Editor and assumed that users who will test this experimental feature, already know that kind of basic about blender.
Context menu in Simulation Editor is the one used in all node editors (but those ones have an Add menu in their header).
I liked when toolbar was giving ability to add nodes in 2.7x. Now, that is limited only to 3 buttons for active tools, toolbar in node editor seems pretty useless.
When amount of active tools is so ridiculously low, we should have a clever way to use toolbar.