yellow dotted wireframe appears when I mistakenly press Shift-t instead of Ctrl-t When I attempt to triangulate a mesh I end up with that dotted yellow bounding box when I mistakenly press Shift+t instead of Ctrl+t.  I cannot get rid of it by using Undo.  

From what I can tell, it has something to do with Texture Space but I cannot find anything in the Object Data panel that will remove it once it's there.  

So does anyone know how to get rid of this and set things back to how they were before I hit that wrong shortcut?
Shift+T does indeed turn on the 'Texture Space' display mode. 

To disable it go to Object> Display> Texture Space and untick the checkbox: