Use ++= for the scaladoc title settings.

Author: cheeseng

build.sbt

@@ -114,4 +114,4 @@ scalacOptions ++= Seq(
   "-Ywarn-dead-code",
 ) ++ (if (scalaBinaryVersion.value == "2.10") Seq.empty else Seq("-Ywarn-unused"))
 
-scalacOptions in (Compile, doc) := Seq("-doc-title", s"ScalaTest + Selenium ${version.value}")
+scalacOptions in (Compile, doc) ++= Seq("-doc-title", s"ScalaTest + Selenium ${version.value}")