Add regtest for complex \once.

diff --git a/input/regression/complex-once.ly b/input/regression/complex-once.ly
new file mode 100644 (file)
index 0000000..c57dd55
--- /dev/null
+++ b/input/regression/complex-once.ly
@@ -0,0 +1,10 @@
+\version "2.15.17"
+
+\header{
+  texidoc= "This tests @code{\once} applied to multiple property operations."
+}
+
+\relative c' {
+  c4 d \hideNotes e4 f |
+  \unHideNotes g a \once \hideNotes b c |
+}