diff --git a/qt/widgets/common/CMakeLists.txt b/qt/widgets/common/CMakeLists.txt
index 79a8a70ec7c559ab7c9019eceacf0db6dbf25e45..89adaae96463bb7a65141b24e93cc7eb9548a44d 100644
--- a/qt/widgets/common/CMakeLists.txt
+++ b/qt/widgets/common/CMakeLists.txt
@@ -152,7 +152,6 @@ set(
   inc/MantidQtWidgets/Common/GenericDialog.h
   inc/MantidQtWidgets/Common/IFunctionView.h
   inc/MantidQtWidgets/Common/HintingLineEdit.h
-  inc/MantidQtWidgets/Common/ISlitCalculator.h
   inc/MantidQtWidgets/Common/InputController.h
   inc/MantidQtWidgets/Common/InstrumentSelector.h
   inc/MantidQtWidgets/Common/LineEditWithClear.h
@@ -524,7 +523,6 @@ set(
   inc/MantidQtWidgets/Common/HintingLineEdit.h
   inc/MantidQtWidgets/Common/CatalogSearch.h
   inc/MantidQtWidgets/Common/CatalogSelector.h
-  inc/MantidQtWidgets/Common/ISlitCalculator.h
   inc/MantidQtWidgets/Common/InstrumentSelector.h
   inc/MantidQtWidgets/Common/InputController.h
   inc/MantidQtWidgets/Common/MantidWSIndexDialog.h