Install missing ui file

qt/python/mantidqt/CMakeLists.txt

@@ -17,6 +17,13 @@ list ( APPEND common_link_libs
   ${PYTHON_LIBRARIES}
 )
 
+# TODO - Should the macro below do this? There is only one ui
+#        file shared between qt4/qt5
+set (UI_FILES dialogs/spectraselectordialog.ui)
+
+install ( FILES ${UI_FILES}
+          DESTINATION     ${LIB_DIR}/mantidqt/dialogs )
+
 # Wrapper module linked against Qt4
 mtd_add_sip_module (
   MODULE_NAME _commonqt4