diff --git a/src/internfile/internfile.cpp b/src/internfile/internfile.cpp
index b44d045f..ba30ca5d 100644
--- a/src/internfile/internfile.cpp
+++ b/src/internfile/internfile.cpp
@@ -547,6 +547,50 @@ void FileInterner::getMissingDescription(FIMissingStore *st, string& out)
     }
 }
 
+void FileInterner::getMissingFromDescription(FIMissingStore *st, const string& in)
+{
+    if (st == 0)
+	return;
+
+    // The "missing" file is text. Each line defines a missing filter
+    // and the list of mime types actually encountered that needed it (see method
+    // getMissingDescription())
+
+    vector<string> lines;
+    stringToTokens(in, lines, "\n");
+
+    for (vector<string>::const_iterator it = lines.begin();
+	 it != lines.end(); it++) {
+	// Lines from the file are like: 
+	//
+	// filter name string (mime1 mime2) 
+	//
+	// We can't be too sure that there will never be a parenthesis
+	// inside the filter string as this comes from the filter
+	// itself. The list part is safer, so we start from the end.
+	const string& line = *it;
+	string::size_type lastopen = line.find_last_of("(");
+	if (lastopen == string::npos)
+	    continue;
+	string::size_type lastclose = line.find_last_of(")");
+	if (lastclose == string::npos || lastclose <= lastopen + 1)
+	    continue;
+	string smtypes = line.substr(lastopen+1, lastclose - lastopen - 1);
+	vector<string> mtypes;
+	stringToTokens(smtypes, mtypes);
+	string filter = line.substr(0, lastopen);
+	trimstring(filter);
+	if (filter.empty())
+	    continue;
+
+	st->m_missingExternal.insert(filter);
+	for (vector<string>::const_iterator itt = mtypes.begin(); 
+	     itt != mtypes.end(); itt++) {
+	    st->m_typesForMissing[filter].insert(*itt);
+	}
+    }
+}
+
 // Helper for extracting a value from a map.
 static inline bool getKeyValue(const map<string, string>& docdata, 
 			       const string& key, string& value)
diff --git a/src/internfile/internfile.h b/src/internfile/internfile.h
index 8acd235b..13e07046 100644
--- a/src/internfile/internfile.h
+++ b/src/internfile/internfile.h
@@ -193,6 +193,8 @@ class FileInterner {
     const string& getReason() const {return m_reason;}
     static void getMissingExternal(FIMissingStore *st, string& missing);
     static void getMissingDescription(FIMissingStore *st, string& desc);
+    // Parse "missing" file contents into memory struct
+    static void getMissingFromDescription(FIMissingStore *st, const string& desc);
     bool ok() {return m_ok;}
 
  private:
diff --git a/src/qtgui/listdialog.h b/src/qtgui/listdialog.h
new file mode 100644
index 00000000..d3ff3d69
--- /dev/null
+++ b/src/qtgui/listdialog.h
@@ -0,0 +1,32 @@
+/*
+ *   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; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   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.,
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+#ifndef LISTDIALOG_H
+#define LISTDIALOG_H
+#include "ui_listdialog.h"
+
+class ListDialog : public QDialog, public Ui::ListDialog {
+    Q_OBJECT
+    public:
+    ListDialog(QWidget * parent = 0) 
+	: QDialog(parent)
+    {
+	setupUi(this);
+    }
+};
+
+
+#endif // LISTDIALOG_H
diff --git a/src/qtgui/listdialog.ui b/src/qtgui/listdialog.ui
new file mode 100644
index 00000000..c9839b78
--- /dev/null
+++ b/src/qtgui/listdialog.ui
@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>ListDialog</class>
+ <widget class="QDialog" name="ListDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>400</width>
+    <height>300</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Dialog</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <widget class="QGroupBox" name="groupBox">
+     <property name="title">
+      <string>GroupBox</string>
+     </property>
+     <layout class="QHBoxLayout" name="horizontalLayout">
+      <item>
+       <widget class="QListWidget" name="listWidget"/>
+      </item>
+     </layout>
+    </widget>
+   </item>
+   <item>
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Ok</set>
+     </property>
+     <property name="centerButtons">
+      <bool>true</bool>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>ListDialog</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>ListDialog</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>
diff --git a/src/qtgui/rclmain.ui b/src/qtgui/rclmain.ui
index e2f19c26..f3c8255d 100644
--- a/src/qtgui/rclmain.ui
+++ b/src/qtgui/rclmain.ui
@@ -138,7 +138,9 @@
     <addaction name="separator"/>
     <addaction name="fileEraseSearchHistoryAction"/>
     <addaction name="fileEraseDocHistoryAction"/>
+    <addaction name="separator"/>
     <addaction name="showMissingHelpers_Action"/>
+    <addaction name="showActiveTypes_Action"/>
     <addaction name="separator"/>
     <addaction name="toggleFullScreenAction"/>
     <addaction name="separator"/>
@@ -169,6 +171,7 @@
     </property>
     <addaction name="userManualAction"/>
     <addaction name="showMissingHelpers_Action"/>
+    <addaction name="showActiveTypes_Action"/>
     <addaction name="separator"/>
     <addaction name="helpAbout_RecollAction"/>
    </widget>
@@ -221,6 +224,14 @@
     <cstring>showMissingHelpers_Action</cstring>
    </property>
   </action>
+  <action name="showActiveTypes_Action">
+   <property name="text">
+    <string>&amp;Show indexed types</string>
+   </property>
+   <property name="name" stdset="0">
+    <cstring>showActiveTypes_Action</cstring>
+   </property>
+  </action>
   <action name="helpAbout_RecollAction">
    <property name="text">
     <string>&amp;About Recoll</string>
diff --git a/src/qtgui/rclmain_w.cpp b/src/qtgui/rclmain_w.cpp
index 6e4bc88b..f22a4eb2 100644
--- a/src/qtgui/rclmain_w.cpp
+++ b/src/qtgui/rclmain_w.cpp
@@ -68,6 +68,7 @@ using std::pair;
 #include "docseqhist.h"
 #include "confguiindex.h"
 #include "restable.h"
+#include "listdialog.h"
 
 using namespace confgui;
 
@@ -225,6 +226,8 @@ void RclMain::init()
 	    this, SLOT(showAboutDialog()));
     connect(showMissingHelpers_Action, SIGNAL(activated()), 
 	    this, SLOT(showMissingHelpers()));
+    connect(showActiveTypes_Action, SIGNAL(activated()), 
+	    this, SLOT(showActiveTypes()));
     connect(userManualAction, SIGNAL(activated()), 
 	    this, SLOT(startManual()));
     connect(toolsDoc_HistoryAction, SIGNAL(activated()), 
@@ -749,6 +752,86 @@ void RclMain::showMissingHelpers()
     QMessageBox::information(this, tr("Missing helper programs"), msg);
 }
 
+void RclMain::showActiveTypes()
+{
+    if (rcldb == 0) {
+	QMessageBox::warning(0, tr("Error"), 
+			     tr("Index not open"),
+			     QMessageBox::Ok, 
+			     QMessageBox::NoButton);
+	return;
+    }
+
+    // Get list of all mime types in index. For this, we use a
+    // wildcard field search on mtype
+    Rcl::TermMatchResult matches;
+    string prefix;
+    if (!rcldb->termMatch(Rcl::Db::ET_WILD, "", "*", matches, -1, "mtype", 
+			  &prefix)) {
+	QMessageBox::warning(0, tr("Error"), 
+			     tr("Index query error"),
+			     QMessageBox::Ok, 
+			     QMessageBox::NoButton);
+	return;
+    }
+
+    // Build the set of mtypes, stripping the prefix
+    set<string> mtypesfromdb;
+    for (list<Rcl::TermMatchEntry>::const_iterator it = matches.entries.begin(); 
+	 it != matches.entries.end(); it++) {
+	mtypesfromdb.insert(it->term.substr(prefix.size()));
+    }
+
+    // All types listed in mimeconf:
+    list<string> mtypesfromconfig = theconfig->getAllMimeTypes();
+
+    // Intersect file system types with config types (those not in the
+    // config can be indexed by name, not by content)
+    set<string> mtypesfromdbconf;
+    for (list<string>::const_iterator it = mtypesfromconfig.begin();
+	 it != mtypesfromconfig.end(); it++) {
+	if (mtypesfromdb.find(*it) != mtypesfromdb.end())
+	    mtypesfromdbconf.insert(*it);
+    }
+
+    // Substract the types for missing helpers (the docs are indexed by name only):
+    string miss = theconfig->getMissingHelperDesc();
+    if (!miss.empty()) {
+	FIMissingStore st;
+	FileInterner::getMissingFromDescription(&st, miss);
+	map<string, set<string> >::const_iterator it;
+	for (it = st.m_typesForMissing.begin(); 
+	     it != st.m_typesForMissing.end(); it++) {
+	    set<string>::const_iterator it1;
+	    for (it1 = it->second.begin(); 
+		 it1 != it->second.end(); it1++) {
+		set<string>::iterator it2 = mtypesfromdbconf.find(*it1);
+		if (it2 != mtypesfromdbconf.end())
+		    mtypesfromdbconf.erase(it2);
+	    }
+	}	
+    }
+    ListDialog dialog;
+    dialog.setWindowTitle(tr("Indexed Mime Types"));
+
+    // Turn the result into a string and display
+    dialog.groupBox->setTitle(tr("Content has been indexed for these mime types:"));
+
+    // We replace the list with an editor so that the user can copy/paste
+    delete dialog.listWidget;
+    QTextEdit *editor = new QTextEdit(dialog.groupBox);
+    editor->setReadOnly(TRUE);
+    dialog.horizontalLayout->addWidget(editor);
+
+    for (set<string>::const_iterator it = mtypesfromdbconf.begin(); 
+	 it != mtypesfromdbconf.end(); it++) {
+	editor->append(QString::fromAscii(it->c_str()));
+    }
+    editor->moveCursor(QTextCursor::Start);
+    editor->ensureCursorVisible();
+    dialog.exec();
+}
+
 // If a preview (toplevel) window gets closed by the user, we need to
 // clean up because there is no way to reopen it. And check the case
 // where the current one is closed
diff --git a/src/qtgui/rclmain_w.h b/src/qtgui/rclmain_w.h
index 2bda5644..2c1a6d0c 100644
--- a/src/qtgui/rclmain_w.h
+++ b/src/qtgui/rclmain_w.h
@@ -69,6 +69,7 @@ public slots:
     virtual void showSpellDialog();
     virtual void showAboutDialog();
     virtual void showMissingHelpers();
+    virtual void showActiveTypes();
     virtual void startManual();
     virtual void startManual(const string&);
     virtual void showDocHistory();
diff --git a/src/qtgui/recoll.pro.in b/src/qtgui/recoll.pro.in
index f2881732..69fe9221 100644
--- a/src/qtgui/recoll.pro.in
+++ b/src/qtgui/recoll.pro.in
@@ -7,6 +7,7 @@ HEADERS += \
         advsearch_w.h \
         confgui/confgui.h \
         confgui/confguiindex.h \
+        listdialog.h \
         preview_w.h \
         rclhelp.h \
         rclmain_w.h \
@@ -41,6 +42,7 @@ SOURCES += \
 
 FORMS   = \
         advsearch.ui \
+        listdialog.ui \
         rclmain.ui \
         restable.ui \
 	spell.ui \
diff --git a/src/rcldb/searchdata.cpp b/src/rcldb/searchdata.cpp
index 774a2854..a3127907 100644
--- a/src/rcldb/searchdata.cpp
+++ b/src/rcldb/searchdata.cpp
@@ -139,6 +139,11 @@ date_range_filter(int y1, int m1, int d1, int y2, int m2, int d2)
 }
 
 // Expand categories and mime type wild card exps
+// Actually, using getAllMimeTypes() here is a bit problematic because
+// there maybe other types in the index, not indexed by content, but
+// which could be searched by file name. It would probably be
+// preferable to do a termMatch() on field "mtype", which would
+// retrieve all values from the index.
 bool SearchData::expandFileTypes(RclConfig *cfg, vector<string>& tps)
 {
     if (!cfg) {