QtHelp

enable-qthelp-flag.patch

diff --git buildconfig/CMake/PyQtFindImpl.cmake buildconfig/CMake/PyQtFindImpl.cmake
index 3595f733df4..ca073c6b837 100644
--- buildconfig/CMake/PyQtFindImpl.cmake
+++ buildconfig/CMake/PyQtFindImpl.cmake
@@ -45,7 +45,7 @@ function (find_pyqt major_version)
     set (PYQT${major_version}_VERSION_TAG "${CMAKE_MATCH_1}" CACHE STRING "The Qt version tag used by PyQt${major_version}'s .sip files" FORCE)
 
     string (REGEX MATCH ".*\npyqt_sip_dir:([^\n]+).*$" _dummy ${_pyqt_config})
-    set (PYQT${major_version}_SIP_DIR "${CMAKE_MATCH_1}" CACHE PATH "The base directory where PyQt${major_version}'s .sip files are installed" FORCE)
+    set (PYQT${major_version}_SIP_DIR "${CMAKE_MATCH_1}" CACHE PATH "The base directory where PyQt${major_version}'s .sip files are installed")
 
     string (REGEX MATCH ".*\npyqt_sip_flags:([^\n]+).*$" _dummy ${_pyqt_config})
     set (PYQT${major_version}_SIP_FLAGS "${CMAKE_MATCH_1}" CACHE STRING "The SIP flags used to build PyQt${major_version}" FORCE)
diff --git qt/widgets/common/CMakeLists.txt qt/widgets/common/CMakeLists.txt
index 60a874c203e..3b4d31f4a8d 100644
--- qt/widgets/common/CMakeLists.txt
+++ qt/widgets/common/CMakeLists.txt
@@ -66,7 +66,6 @@ set(
   src/ParseKeyValueString.cpp
   src/pixmaps.cpp
   src/PluginLibraries.cpp
-  src/pqHelpWindow.cxx
   src/ProcessingAlgoWidget.cpp
   src/ProgressableView.cpp
   src/PropertyHandler.cpp
@@ -187,7 +186,6 @@ set(
   inc/MantidQtWidgets/Common/FileFinderWidget.h
   inc/MantidQtWidgets/Common/NotificationService.h
   inc/MantidQtWidgets/Common/OptionsPropertyWidget.h
-  inc/MantidQtWidgets/Common/pqHelpWindow.h
   inc/MantidQtWidgets/Common/ProcessingAlgoWidget.h
   inc/MantidQtWidgets/Common/PropertyHandler.h
   inc/MantidQtWidgets/Common/PropertyWidget.h
@@ -844,29 +842,34 @@ if(ENABLE_WORKBENCH)
     Qt5
     COMPONENTS
       Concurrent
-      Help
       Network
       PrintSupport
     REQUIRED
   )
-  # Prefer WebEngineWidgets over WebkitWidgets
-  unset(Qt5_FOUND)
-  find_package(Qt5 COMPONENTS WebEngineWidgets QUIET)
-  if(Qt5_FOUND)
-    set(_webwidgets_tgt Qt5::WebEngineWidgets)
-  else()
-    find_package(Qt5 COMPONENTS WebKitWidgets QUIET)
+  option(ENABLE_QTHELP "If True then enable help via QtHelp module" ON)
+  set(QTHELP_DEF)
+  if(ENABLE_QTHELP)
+    # Prefer WebEngineWidgets over WebkitWidgets
+    unset(Qt5_FOUND)
+    find_package(Qt5 COMPONENTS Help WebEngineWidgets QUIET)
     if(Qt5_FOUND)
-      set(_webwidgets_tgt Qt5::WebKitWidgets)
-      set(_webengine_def USE_QTWEBKIT)
+      set(_webwidgets_tgt Qt5::Help Qt5::WebEngineWidgets)
     else()
-      message(
-        FATAL_ERROR
-          "Unable to find suitable module for web widgets. Tried: WebEnginewidgets, WebKitWidgets"
-      )
+      find_package(Qt5 COMPONENTS Help WebKitWidgets QUIET)
+      if(Qt5_FOUND)
+        set(_webwidgets_tgt Qt5::Help Qt5::WebKitWidgets)
+        set(_webengine_def USE_QTWEBKIT)
+      else()
+        message(
+          FATAL_ERROR
+            "Unable to find suitable module for web widgets. Tried: WebEnginewidgets, WebKitWidgets"
+        )
+      endif()
     endif()
+    set(QTHELP_DEF "ENABLE_QTHELP ${_webengine_def}")
+    list(APPEND QT5_SRC_FILES src/pqHelpWindow.cxx)
+    list(APPEND QT5_MOC_FILES inc/MantidQtWidgets/Common/pqHelpWindow.h)
   endif()
-
 endif()
 
 mtd_add_qt_library(
@@ -913,7 +916,7 @@ mtd_add_qt_library(
     IN_MANTIDQT_COMMON
     QSCINTILLA_DLL
     QT5_DEFS
-    ${_webengine_def}
+    ${QTHELP_DEF}
   INCLUDE_DIRS
     inc
   SYSTEM_INCLUDE_DIRS
@@ -924,7 +927,6 @@ mtd_add_qt_library(
     PythonInterfaceCore
   QT5_LINK_LIBS
     Qt5::Concurrent
-    Qt5::Help
     Qt5::Network
     Qt5::PrintSupport
     ${_webwidgets_tgt}
diff --git qt/widgets/common/inc/MantidQtWidgets/Common/MantidHelpWindow.h qt/widgets/common/inc/MantidQtWidgets/Common/MantidHelpWindow.h
index d4f39094c92..408e49795ba 100644
--- qt/widgets/common/inc/MantidQtWidgets/Common/MantidHelpWindow.h
+++ qt/widgets/common/inc/MantidQtWidgets/Common/MantidHelpWindow.h
@@ -11,6 +11,8 @@
 #include <QWidget>
 #include <string>
 
+#if defined(ENABLE_QTHELP)
+
 // forward declaration
 class QHelpEngine;
 class QString;
@@ -73,4 +75,22 @@ public slots:
 };
 
 } // namespace MantidWidgets
-} // namespace MantidQt
\ No newline at end of file
+} // namespace MantidQt
+
+#else
+
+namespace MantidQt {
+namespace MantidWidgets {
+
+class EXPORT_OPT_MANTIDQT_COMMON MantidHelpWindow
+    : public API::MantidHelpInterface {
+  Q_OBJECT
+
+public:
+  using MantidHelpInterface::MantidHelpInterface;
+  static bool helpWindowExists() { return false; }
+};
+} // namespace MantidWidgets
+} // namespace MantidQt
+
+#endif
diff --git qt/widgets/common/src/MantidHelpWindow.cpp qt/widgets/common/src/MantidHelpWindow.cpp
index 05b1195e8a1..23c4627bae6 100644
--- qt/widgets/common/src/MantidHelpWindow.cpp
+++ qt/widgets/common/src/MantidHelpWindow.cpp
@@ -5,6 +5,9 @@
 //   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
 // SPDX - License - Identifier: GPL - 3.0 +
 #include "MantidQtWidgets/Common/MantidHelpWindow.h"
+
+#if defined(ENABLE_QTHELP)
+
 #include "MantidAPI/AlgorithmManager.h"
 #include "MantidKernel/ConfigService.h"
 #include "MantidKernel/Logger.h"
@@ -494,3 +497,7 @@ void MantidHelpWindow::warning(const QString &msg) {
 
 } // namespace MantidWidgets
 } // namespace MantidQt
+
+#else
+
+#endif