diff -r 6e8b807bda4b -r ba39a1d396c0 QTfrontend/model/ThemeFilterProxyModel.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/QTfrontend/model/ThemeFilterProxyModel.cpp	Sun Jun 10 19:12:26 2018 +0200
@@ -0,0 +1,71 @@
+/*
+ * Hedgewars, a free turn based strategy game
+ * Copyright (c) 2004-2018 Andrey Korotaev <unC0Rr@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/**
+ * @file
+ * @brief ThemeFilterProxyModel class implementation
+ */
+
+#include "ThemeModel.h"
+#include "ThemeFilterProxyModel.h"
+
+ThemeFilterProxyModel::ThemeFilterProxyModel(QObject *parent)
+    : QSortFilterProxyModel(parent)
+{
+    isFilteringDLC = false;
+    isFilteringHidden = false;
+}
+
+bool ThemeFilterProxyModel::filterAcceptsRow(int sourceRow, const QModelIndex & sourceParent) const
+{
+    QModelIndex index = sourceModel()->index(sourceRow, 0, sourceParent);
+    bool searchOkay = true;
+    if(!filterRegExp().isEmpty())
+    {
+        // Check regular expression set by the theme chooser search
+        QString name = index.data(ThemeModel::ActualNameRole).toString();
+        int in = filterRegExp().indexIn(name);
+        searchOkay = in != -1;
+    }
+
+    if(isFilteringDLC || isFilteringHidden)
+    {
+        bool isDLC = index.data(ThemeModel::IsDlcRole).toBool();
+        bool isHidden = index.data(ThemeModel::IsHiddenRole).toBool();
+
+        return ( ((isFilteringDLC && !isDLC) || !isFilteringDLC) &&
+                 ((isFilteringHidden && !isHidden) || !isFilteringHidden) ) &&
+               searchOkay;
+    }
+    else
+    {
+        return searchOkay;
+    }
+}
+
+void ThemeFilterProxyModel::setFilterDLC(bool enable)
+{
+    isFilteringDLC = enable;
+    invalidateFilter();
+}
+
+void ThemeFilterProxyModel::setFilterHidden(bool enable)
+{
+    isFilteringHidden = enable;
+    invalidateFilter();
+}