Validate dataSelector. Refs #8938.

- Although there is a dataSelector specific validator class (`UserInputValidator`), it is not possible to access it from `MantidQtCustomDialogs`.

Code/Mantid/MantidQt/CustomDialogs/inc/MantidQtCustomDialogs/CatalogPublishDialog.h

@@ -53,6 +53,10 @@ namespace MantidQt
         /// Set the "FileName" property when a file is selected from the file browser.
         void fileSelected();
 
+      protected:
+        /// Overridden to enable dataselector validators
+        void accept();
+
       protected:
         /// The form generated by QT Designer.
         Ui::CatalogPublishDialog m_uiForm;

Code/Mantid/MantidQt/CustomDialogs/src/CatalogPublishDialog.cpp

@@ -110,5 +110,17 @@ namespace MantidQt
       setPropertyValue("FileName", true);
     }
 
+    /**
+     * Overridden to enable dataselector validators.
+     */
+    void CatalogPublishDialog::accept()
+    {
+      if (!m_uiForm.dataSelector->isValid())
+      {
+        QMessageBox::critical(this,"Error in catalog publishing.",m_uiForm.dataSelector->getProblem());
+        return;
+      }
+      AlgorithmDialog::accept();
+    }
   }
 }