diff --git a/src/osg/Shader.cpp b/src/osg/Shader.cpp
index 270d17835..4d3485565 100644
--- a/src/osg/Shader.cpp
+++ b/src/osg/Shader.cpp
@@ -656,7 +656,7 @@ void Shader::PerContextShader::compileShader(osg::State& state)
                 if ((end_of_line-start_of_line)>=8 && source.compare(start_of_line, 8, "#version")==0)
                 {
                     versionLine = source.substr(start_of_line, end_of_line-start_of_line+1);
-                    if (source[source.size()-1]!='\n') source.push_back('\n');
+                    if (versionLine[versionLine.size()-1]!='\n') versionLine.push_back('\n');
 
                     source.insert(start_of_line, "// following version spec has been automatically reassigned to start of source list: ");