Add Text_spanner_engraver to Dynamics context.
--- /dev/null
+\version "2.13.9"
+
+\header {
+ texidoc = "Text spanners work in the @code{Dynamics} context."
+}
+
+<<
+ \new Staff \relative c' {
+ c1 | c
+ }
+ \new Dynamics {
+ \override TextSpanner #'(bound-details left text) = #"rit."
+ s1\startTextSpan
+ s1\stopTextSpan
+ }
+ \new Staff \relative c' {
+ c1 | c
+ }
+>>
\consists "New_dynamic_engraver"
\consists "Dynamic_align_engraver"
\consists "Text_engraver"
+ \consists "Text_spanner_engraver"
\consists "Skip_event_swallow_translator"
\consists "Axis_group_engraver"