diff --git a/src/windowBed/windowMain.cpp b/src/windowBed/windowMain.cpp
index 982109e403781383072f2597de3e56e8b5114c1d..7d70f3a4359951b233cf83b31e8f1812390f8a1f 100644
--- a/src/windowBed/windowMain.cpp
+++ b/src/windowBed/windowMain.cpp
@@ -111,7 +111,7 @@ int main(int argc, char* argv[]) {
         else if (PARAMETER_CHECK("-sm", 3, parameterLength)) {
             matchOnSameStrand = true;
         }
-        else if (PARAMETER_CHECK("-sm", 3, parameterLength)) {
+        else if (PARAMETER_CHECK("-Sm", 3, parameterLength)) {
             matchOnDiffStrand = true;
         }
         else if (PARAMETER_CHECK("-w", 2, parameterLength)) {