diff --git a/GUI/Model/Type/SetWithModel.h b/GUI/Model/Type/SetWithModel.h
new file mode 100644
index 0000000000000000000000000000000000000000..4007050f56712ed39f8806a134932231d142ded8
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+++ b/GUI/Model/Type/SetWithModel.h
@@ -0,0 +1,113 @@
+//  ************************************************************************************************
+//
+//  BornAgain: simulate and fit reflection and scattering
+//
+//! @file      GUI/Model/Type/SetWithModel.h
+//! @brief     Defines and implements templated class VectorWC.
+//!
+//! @homepage  http://www.bornagainproject.org
+//! @license   GNU General Public License v3 or higher (see COPYING)
+//! @copyright Forschungszentrum Jülich GmbH 2018
+//! @authors   Scientific Computing Group at MLZ (see CITATION, AUTHORS)
+//
+//  ************************************************************************************************
+
+#ifdef SWIG
+#error no need to expose this header to Swig
+#endif // SWIG
+#ifndef BORNAGAIN_GUI_MODEL_TYPE_SETWITHMODEL_H
+#define BORNAGAIN_GUI_MODEL_TYPE_SETWITHMODEL_H
+
+#include "Base/Types/OwningVector.h"
+#include "Base/Util/Assert.h"
+
+//! An OwningVector with a current index.
+
+template <class T> class VectorWC : public OwningVector<T> {
+    using super = OwningVector<T>;
+
+public:
+    void push_back(T* e)
+    {
+        super::push_back(e);
+        m_current_index = super::size() - 1;
+    }
+    void insert_at(size_t i, T* e)
+    {
+        super::insert_at(i, e);
+        m_current_index = i;
+    }
+    void replace_at(size_t i, T* e)
+    {
+        super::replace_at(i, e);
+        m_current_index = i;
+    }
+    void delete_element(const T* e)
+    {
+        super::delete_element(e);
+        update_current();
+    }
+    void delete_at(size_t i)
+    {
+        super::delete_at(i);
+        update_current();
+    }
+    void delete_current()
+    {
+        ASSERT(m_current_index != size_t(-1));
+        super::delete_at(m_current_index);
+        update_current();
+    }
+    T* release_at(size_t i)
+    {
+        super::release_at(i);
+        update_current();
+    }
+    T* release_back()
+    {
+        super::release_back();
+        update_current();
+    }
+    T* release_front()
+    {
+        super::release_front();
+        update_current();
+    }
+    void swap(size_t from, size_t to)
+    {
+        super::swap(from, to);
+        // TODO update m_current_index ?
+    }
+    void clear()
+    {
+        super::clear();
+        m_current_index = -1;
+    }
+
+    void setCurrentIndex(size_t i)
+    {
+        ASSERT(i < super::size() || i == size_t(-1));
+        if (i != m_current_index)
+            m_current_index = i;
+    }
+    size_t currentIndex() const { return m_current_index; }
+    const T* currentItem() const
+    {
+        return m_current_index < super::size() ? super::at(m_current_index) : (T*)nullptr;
+    }
+    T* currentItem()
+    {
+        return m_current_index < super::size() ? super::at(m_current_index) : (T*)nullptr;
+    }
+
+private:
+    void update_current()
+    {
+        if (m_current_index == super::size())
+            m_current_index = super::size() - 1;
+    }
+
+    size_t m_current_index = -1;
+};
+
+#endif // BORNAGAIN_GUI_MODEL_TYPE_SETWITHMODEL_H