diff --git a/CMakeLists.txt b/CMakeLists.txt
index e81dc64c5..ad050458e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1362,7 +1362,7 @@ set_target_properties (wsjtx_udp-static PROPERTIES
   )
 target_compile_definitions (wsjtx_udp-static PUBLIC UDP_STATIC_DEFINE)
 #qt5_use_modules (wsjtx_udp Network)
-qt5_use_modules (wsjtx_udp-static Network)
+qt5_use_modules (wsjtx_udp-static Network Gui)
 generate_export_header (wsjtx_udp-static BASE_NAME udp)
 
 add_executable (udp_daemon UDPExamples/UDPDaemon.cpp UDPExamples/udp_daemon.rc ${WSJTX_ICON_FILE})
diff --git a/MessageClient.cpp b/MessageClient.cpp
index 2b6d9e308..68d6f0fdc 100644
--- a/MessageClient.cpp
+++ b/MessageClient.cpp
@@ -10,6 +10,7 @@
 #include <QQueue>
 #include <QByteArray>
 #include <QHostAddress>
+#include <QColor>
 
 #include "NetworkMessage.hpp"
 
@@ -218,6 +219,20 @@ void MessageClient::impl::parse_message (QByteArray const& msg)
               }
               break;
 
+            case NetworkMessage::HighlightCallsign:
+              {
+                QByteArray call;
+                QColor bg;      // default invalid color
+                QColor fg;      // default invalid color
+                bool last_only {false};
+                in >> call >> bg >> fg >> last_only;
+                if (check_status (in) != Fail && call.size ())
+                  {
+                    Q_EMIT self_->highlight_callsign (QString::fromUtf8 (call), bg, fg, last_only);
+                  }
+              }
+              break;
+
             default:
               // Ignore
               //
diff --git a/MessageClient.hpp b/MessageClient.hpp
index f0719ac55..be524fdb8 100644
--- a/MessageClient.hpp
+++ b/MessageClient.hpp
@@ -11,6 +11,7 @@
 
 class QByteArray;
 class QHostAddress;
+class QColor;
 
 //
 // MessageClient - Manage messages sent and replies received from a
@@ -95,6 +96,10 @@ public:
   // message text
   Q_SIGNAL void free_text (QString const&, bool send);
 
+  // this signal is emitted if the server has sent a highlight
+  // callsign request for the specified call
+  Q_SIGNAL void highlight_callsign (QString const& callsign, QColor const& bg, QColor const& fg, bool last_only);
+
   // this signal is emitted when network errors occur or if a host
   // lookup fails
   Q_SIGNAL void error (QString const&) const;
diff --git a/MessageServer.cpp b/MessageServer.cpp
index 724da4afc..b5a719e74 100644
--- a/MessageServer.cpp
+++ b/MessageServer.cpp
@@ -480,3 +480,16 @@ void MessageServer::location (QString const& id, QString const& loc)
     m_->send_message (out, message, iter.value ().sender_address_, (*iter).sender_port_);
   }
 }
+
+void MessageServer::highlight_callsign (QString const& id, QString const& callsign
+                                        , QColor const& bg, QColor const& fg, bool last_only)
+{
+  auto iter = m_->clients_.find (id);
+  if (iter != std::end (m_->clients_))
+  {
+    QByteArray message;
+    NetworkMessage::Builder out {&message, NetworkMessage::HighlightCallsign, id, (*iter).negotiated_schema_number_};
+    out << callsign.toUtf8 () << bg << fg << last_only;
+    m_->send_message (out, message, iter.value ().sender_address_, (*iter).sender_port_);
+  }
+}
diff --git a/MessageServer.hpp b/MessageServer.hpp
index 77c976fa4..bb7501529 100644
--- a/MessageServer.hpp
+++ b/MessageServer.hpp
@@ -5,6 +5,7 @@
 #include <QTime>
 #include <QDateTime>
 #include <QHostAddress>
+#include <QColor>
 
 #include "udp_export.h"
 #include "Radio.hpp"
@@ -62,6 +63,12 @@ public:
   // ask the client with identification 'id' to set the location provided
   Q_SLOT void location (QString const& id, QString const& location);
 
+  // ask the client with identification 'id' to highlight the callsign
+  // specified with the given colors
+  Q_SLOT void highlight_callsign (QString const& id, QString const& callsign
+                                  , QColor const& bg = QColor {}, QColor const& fg = QColor {}
+                                  , bool last_only = false);
+
   // the following signals are emitted when a client broadcasts the
   // matching message
   Q_SIGNAL void client_opened (QString const& id, QString const& version, QString const& revision);
diff --git a/NetworkMessage.hpp b/NetworkMessage.hpp
index 479575a32..acf64fb32 100644
--- a/NetworkMessage.hpp
+++ b/NetworkMessage.hpp
@@ -350,7 +350,7 @@
  *
  * Logged ADIF    Out      12                     quint32
  *                         Id (unique key)        utf8
- *                         ADIF text              ASCII (serialized like utf8)
+ *                         ADIF text              utf8
  *
  *      The  logged ADIF  message is  sent to  the server(s)  when the
  *      WSJT-X user accepts the "Log  QSO" dialog by clicking the "OK"
@@ -368,6 +368,27 @@
  *      Note that  receiving applications can treat  the whole message
  *      as a valid ADIF file with one record without special parsing.
  *
+ *
+ * Highlight Callsign In   13                     quint32
+ *                         Id (unique key)        utf8
+ *                         Callsign               utf8
+ *                         Background Color       QColor
+ *                         Foreground Color       QColor
+ *                         Highlight last         bool
+ *
+ *      The server  may send  this message at  any time.   The message
+ *      specifies  the background  and foreground  color that  will be
+ *      used  to  highlight  the  specified callsign  in  the  decoded
+ *      messages  printed  in  the  Band Activity  panel.  The  WSJT-X
+ *      clients maintain a list of such instructions and apply them to
+ *      all decoded  messages in the  band activity window.   To clear
+ *      highlighting send an  invalid QColor value for  either or both
+ *      of the background and foreground fields.
+ *
+ *      The "Highlight last"  field allows the sender  to request that
+ *      the  last  instance  only  instead of  all  instances  of  the
+ *      specified  call  be  highlighted  or  have  it's  highlighting
+ *      cleared.
  */
 
 #include <QDataStream>
@@ -396,6 +417,7 @@ namespace NetworkMessage
       WSPRDecode,
       Location,
       LoggedADIF,
+      HighlightCallsign,
       maximum_message_type_     // ONLY add new message types
                                 // immediately before here
     };
diff --git a/UDPExamples/ClientWidget.cpp b/UDPExamples/ClientWidget.cpp
index 001041cae..06b09ba4d 100644
--- a/UDPExamples/ClientWidget.cpp
+++ b/UDPExamples/ClientWidget.cpp
@@ -115,9 +115,10 @@ namespace
 
 ClientWidget::ClientWidget (QAbstractItemModel * decodes_model, QAbstractItemModel * beacons_model
                             , QString const& id, QString const& version, QString const& revision
-                            , QWidget * parent)
+                            , QListWidget const * calls_of_interest, QWidget * parent)
   : QDockWidget {make_title (id, version, revision), parent}
   , id_ {id}
+  , calls_of_interest_ {calls_of_interest}
   , decodes_proxy_model_ {id_}
   , decodes_table_view_ {new QTableView}
   , beacons_table_view_ {new QTableView}
@@ -216,11 +217,27 @@ ClientWidget::ClientWidget (QAbstractItemModel * decodes_model, QAbstractItemMod
   // setMinimumSize (QSize {550, 0});
   setFeatures (DockWidgetMovable | DockWidgetFloatable);
   setAllowedAreas (Qt::BottomDockWidgetArea);
+  setFloating (true);
 
   // connect up table view signals
   connect (decodes_table_view_, &QTableView::doubleClicked, this, [this] (QModelIndex const& index) {
       Q_EMIT do_reply (decodes_proxy_model_.mapToSource (index), QApplication::keyboardModifiers () >> 24);
     });
+
+  // tell new client about calls of interest
+  for (int row = 0; row < calls_of_interest_->count (); ++row)
+    {
+      Q_EMIT highlight_callsign (id_, calls_of_interest_->item (row)->text (), QColor {Qt::blue}, QColor {Qt::yellow});
+    }
+}
+
+ClientWidget::~ClientWidget ()
+{
+  for (int row = 0; row < calls_of_interest_->count (); ++row)
+    {
+      // tell client to forget calls of interest
+      Q_EMIT highlight_callsign (id_, calls_of_interest_->item (row)->text ());
+    }
 }
 
 void ClientWidget::update_status (QString const& id, Frequency f, QString const& mode, QString const& dx_call
diff --git a/UDPExamples/ClientWidget.hpp b/UDPExamples/ClientWidget.hpp
index 0cec23e7a..29059bfa5 100644
--- a/UDPExamples/ClientWidget.hpp
+++ b/UDPExamples/ClientWidget.hpp
@@ -11,6 +11,7 @@
 
 class QAbstractItemModel;
 class QModelIndex;
+class QColor;
 
 using Frequency = MessageServer::Frequency;
 
@@ -22,7 +23,8 @@ class ClientWidget
 public:
   explicit ClientWidget (QAbstractItemModel * decodes_model, QAbstractItemModel * beacons_model
                          , QString const& id, QString const& version, QString const& revision
-                         , QWidget * parent = nullptr);
+                         , QListWidget const * calls_of_interest, QWidget * parent = nullptr);
+  ~ClientWidget ();
 
   bool fast_mode () const {return fast_mode_;}
 
@@ -43,10 +45,14 @@ public:
   Q_SIGNAL void do_reply (QModelIndex const&, quint8 modifier);
   Q_SIGNAL void do_halt_tx (QString const& id, bool auto_only);
   Q_SIGNAL void do_free_text (QString const& id, QString const& text, bool);
-  Q_SIGNAL void location (QString const &id, QString const &text);
+  Q_SIGNAL void location (QString const& id, QString const& text);
+  Q_SIGNAL void highlight_callsign (QString const& id, QString const& call
+                                    , QColor const& bg = QColor {}, QColor const& fg = QColor {}
+                                    , bool last_only = false);
 
 private:
   QString id_;
+  QListWidget const * calls_of_interest_;
   class IdFilterModel final
     : public QSortFilterProxyModel
   {
diff --git a/UDPExamples/MessageAggregatorMainWindow.cpp b/UDPExamples/MessageAggregatorMainWindow.cpp
index 324c7d0e5..1d1dce5d6 100644
--- a/UDPExamples/MessageAggregatorMainWindow.cpp
+++ b/UDPExamples/MessageAggregatorMainWindow.cpp
@@ -36,6 +36,11 @@ MessageAggregatorMainWindow::MessageAggregatorMainWindow ()
   , server_ {new MessageServer {this}}
   , multicast_group_line_edit_ {new QLineEdit}
   , log_table_view_ {new QTableView}
+  , add_call_of_interest_action_ {new QAction {tr ("&Add callsign"), this}}
+  , delete_call_of_interest_action_ {new QAction {tr ("&Delete callsign"), this}}
+  , last_call_of_interest_action_ {new QAction {tr ("&Highlight last only"), this}}
+  , call_of_interest_bg_colour_action_ {new QAction {tr ("&Background colour"), this}}
+  , call_of_interest_fg_colour_action_ {new QAction {tr ("&Foreground colour"), this}}
 {
   // logbook
   int column {0};
@@ -83,6 +88,91 @@ MessageAggregatorMainWindow::MessageAggregatorMainWindow ()
   setDockOptions (AnimatedDocks | AllowNestedDocks | AllowTabbedDocks);
   setTabPosition (Qt::BottomDockWidgetArea, QTabWidget::North);
 
+  QDockWidget * calls_dock {new QDockWidget {tr ("Calls of Interest"), this}};
+  calls_dock->setAllowedAreas (Qt::RightDockWidgetArea);
+  calls_of_interest_ = new QListWidget {calls_dock};
+  calls_of_interest_->setContextMenuPolicy (Qt::ActionsContextMenu);
+  calls_of_interest_->insertAction (nullptr, add_call_of_interest_action_);
+  connect (add_call_of_interest_action_, &QAction::triggered, [this] () {
+      auto item = new QListWidgetItem {};
+      item->setFlags (item->flags () | Qt::ItemIsEditable);
+      item->setData (Qt::UserRole, QString {});
+      calls_of_interest_->addItem (item);
+      calls_of_interest_->editItem (item);
+    });
+  calls_of_interest_->insertAction (nullptr, delete_call_of_interest_action_);
+  connect (delete_call_of_interest_action_, &QAction::triggered, [this] () {
+      for (auto item : calls_of_interest_->selectedItems ())
+        {
+          auto old_call = item->data (Qt::UserRole);
+          if (old_call.isValid ()) change_highlighting (old_call.toString ());
+          delete item;
+        }
+    });
+  calls_of_interest_->insertAction (nullptr, last_call_of_interest_action_);
+  connect (last_call_of_interest_action_, &QAction::triggered, [this] () {
+      for (auto item : calls_of_interest_->selectedItems ())
+        {
+          auto old_call = item->data (Qt::UserRole);
+          change_highlighting (old_call.toString ());
+          change_highlighting (old_call.toString ()
+                               , item->background ().color (), item->foreground ().color (), true);
+          delete item;
+        }
+    });
+  calls_of_interest_->insertAction (nullptr, call_of_interest_bg_colour_action_);
+  connect (call_of_interest_bg_colour_action_, &QAction::triggered, [this] () {
+      for (auto item : calls_of_interest_->selectedItems ())
+        {
+          auto old_call = item->data (Qt::UserRole);
+          auto new_colour = QColorDialog::getColor (item->background ().color ()
+                                                    , this, tr ("Select background color"));
+          if (new_colour.isValid ())
+            {
+              change_highlighting (old_call.toString (), new_colour, item->foreground ().color ());
+              item->setBackground (new_colour);
+            }
+        }
+    });
+  calls_of_interest_->insertAction (nullptr, call_of_interest_fg_colour_action_);
+  connect (call_of_interest_fg_colour_action_, &QAction::triggered, [this] () {
+      for (auto item : calls_of_interest_->selectedItems ())
+        {
+          auto old_call = item->data (Qt::UserRole);
+          auto new_colour = QColorDialog::getColor (item->foreground ().color ()
+                                                    , this, tr ("Select foreground color"));
+          if (new_colour.isValid ())
+            {
+              change_highlighting (old_call.toString (), item->background ().color (), new_colour);
+              item->setForeground (new_colour);
+            }
+        }
+    });
+  connect (calls_of_interest_, &QListWidget::itemChanged, [this] (QListWidgetItem * item) {
+      auto old_call = item->data (Qt::UserRole);
+      auto new_call = item->text ().toUpper ();
+      if (new_call != old_call)
+        {
+          // tell all clients
+          if (old_call.isValid ())
+            {
+              change_highlighting (old_call.toString ());
+            }
+          item->setData (Qt::UserRole, new_call);
+          item->setText (new_call);
+          auto bg = item->listWidget ()->palette ().text ().color ();
+          auto fg = item->listWidget ()->palette ().base ().color ();
+          item->setBackground (bg);
+          item->setForeground (fg);
+          change_highlighting (new_call, bg, fg);
+        }
+    });
+
+  calls_dock->setWidget (calls_of_interest_);
+  addDockWidget (Qt::RightDockWidgetArea, calls_dock);
+  view_menu_->addAction (calls_dock->toggleViewAction ());
+  view_menu_->addSeparator ();
+
   // connect up server
   connect (server_, &MessageServer::error, [this] (QString const& message) {
       QMessageBox::warning (this, QApplication::applicationName (), tr ("Network Error"), message);
@@ -144,7 +234,7 @@ void MessageAggregatorMainWindow::log_qso (QString const& /*id*/, QDateTime time
 
 void MessageAggregatorMainWindow::add_client (QString const& id, QString const& version, QString const& revision)
 {
-  auto dock = new ClientWidget {decodes_model_, beacons_model_, id, version, revision, this};
+  auto dock = new ClientWidget {decodes_model_, beacons_model_, id, version, revision, calls_of_interest_, this};
   dock->setAttribute (Qt::WA_DeleteOnClose);
   auto view_action = dock->toggleViewAction ();
   view_action->setEnabled (true);
@@ -159,8 +249,9 @@ void MessageAggregatorMainWindow::add_client (QString const& id, QString const&
   connect (dock, &ClientWidget::do_free_text, server_, &MessageServer::free_text);
   connect (dock, &ClientWidget::location, server_, &MessageServer::location);
   connect (view_action, &QAction::toggled, dock, &ClientWidget::setVisible);
+  connect (dock, &ClientWidget::highlight_callsign, server_, &MessageServer::highlight_callsign);
   dock_widgets_[id] = dock;
-  server_->replay (id);
+  server_->replay (id);         // request decodes and status
 }
 
 void MessageAggregatorMainWindow::remove_client (QString const& id)
@@ -173,4 +264,21 @@ void MessageAggregatorMainWindow::remove_client (QString const& id)
     }
 }
 
+MessageAggregatorMainWindow::~MessageAggregatorMainWindow ()
+{
+  for (auto client : dock_widgets_)
+    {
+      delete client;
+    }
+}
+
+void MessageAggregatorMainWindow::change_highlighting (QString const& call, QColor const& bg, QColor const& fg
+                                                       , bool last_only)
+{
+  for (auto id : dock_widgets_.keys ())
+    {
+      server_->highlight_callsign (id, call, bg, fg, last_only);
+    }
+}
+
 #include "moc_MessageAggregatorMainWindow.cpp"
diff --git a/UDPExamples/MessageAggregatorMainWindow.hpp b/UDPExamples/MessageAggregatorMainWindow.hpp
index 4ee5bface..b699bee93 100644
--- a/UDPExamples/MessageAggregatorMainWindow.hpp
+++ b/UDPExamples/MessageAggregatorMainWindow.hpp
@@ -15,6 +15,7 @@ class BeaconsModel;
 class QLineEdit;
 class QTableView;
 class ClientWidget;
+class QListWidget;
 
 using Frequency = MessageServer::Frequency;
 
@@ -25,6 +26,7 @@ class MessageAggregatorMainWindow
 
 public:
   MessageAggregatorMainWindow ();
+  ~MessageAggregatorMainWindow ();
 
   Q_SLOT void log_qso (QString const& /*id*/, QDateTime time_off, QString const& dx_call, QString const& dx_grid
                        , Frequency dial_frequency, QString const& mode, QString const& report_sent
@@ -35,6 +37,12 @@ public:
 private:
   void add_client (QString const& id, QString const& version, QString const& revision);
   void remove_client (QString const& id);
+  void change_highlighting (QString const& call, QColor const& bg = QColor {}, QColor const& fg = QColor {},
+                            bool last_only = false);
+
+  // maps client id to widgets
+  using ClientsDictionary = QHash<QString, ClientWidget *>;
+  ClientsDictionary dock_widgets_;
 
   QStandardItemModel * log_;
   QMenu * view_menu_;
@@ -43,10 +51,12 @@ private:
   MessageServer * server_;
   QLineEdit * multicast_group_line_edit_;
   QTableView * log_table_view_;
-
-  // maps client id to widgets
-  using ClientsDictionary = QHash<QString, ClientWidget *>;
-  ClientsDictionary dock_widgets_;
+  QListWidget * calls_of_interest_;
+  QAction * add_call_of_interest_action_;
+  QAction * delete_call_of_interest_action_;
+  QAction * last_call_of_interest_action_;
+  QAction * call_of_interest_bg_colour_action_;
+  QAction * call_of_interest_fg_colour_action_;
 };
 
 #endif
diff --git a/displaytext.cpp b/displaytext.cpp
index 0fa3682d7..a52d02b91 100644
--- a/displaytext.cpp
+++ b/displaytext.cpp
@@ -72,7 +72,7 @@ void DisplayText::insertLineSpacer(QString const& line)
   appendText (line, "#d3d3d3");
 }
 
-void DisplayText::appendText(QString const& text, QColor bg)
+void DisplayText::appendText(QString const& text, QColor bg, QString const& call1, QString const& call2)
 {
   auto cursor = textCursor ();
   cursor.movePosition (QTextCursor::End);
@@ -89,7 +89,59 @@ void DisplayText::appendText(QString const& text, QColor bg)
     {
       cursor.insertBlock (block_format);
     }
-  cursor.insertText (text);
+
+  QTextCharFormat format = cursor.charFormat();
+  format.clearBackground();
+  int text_index {0};
+  if (call1.size ())
+    {
+      auto call_index = text.indexOf (call1);
+      if (call_index != -1) // sanity check
+        {
+          auto pos = highlighted_calls_.find (call1);
+          if (pos != highlighted_calls_.end ())
+            {
+              cursor.insertText(text.left (call_index), format);
+              if (pos.value ().first.isValid ())
+                {
+                  format.setBackground (pos.value ().first);
+                }
+              if (pos.value ().second.isValid ())
+                {
+                  format.setForeground (pos.value ().second);
+                }
+              cursor.insertText(text.mid (call_index, call1.size ()), format);
+              text_index = call_index + call1.size ();
+            }
+        }
+    }
+  if (call2.size ())
+    {
+      auto call_index = text.indexOf (call2, text_index);
+      if (call_index != -1) // sanity check
+        {
+          auto pos = highlighted_calls_.find (call2);
+          if (pos != highlighted_calls_.end ())
+            {
+              format.setBackground (bg);
+              format.clearForeground ();
+              cursor.insertText(text.mid (text_index, call_index - text_index), format);
+              if (pos.value ().second.isValid ())
+                {
+                  format.setBackground (pos.value ().first);
+                }
+              if (pos.value ().second.isValid ())
+                {
+                  format.setForeground (pos.value ().second);
+                }
+              cursor.insertText(text.mid (call_index, call2.size ()), format);
+              text_index = call_index + call2.size ();
+            }
+        }
+    }
+  format.setBackground (bg);
+  format.clearForeground ();
+  cursor.insertText(text.mid (text_index), format);
 
   // position so viewport scrolled to left
   cursor.movePosition (QTextCursor::StartOfLine);
@@ -210,13 +262,16 @@ void DisplayText::displayDecodedText(DecodedText const& decodedText, QString con
     bg = color_MyCall;
   }
   auto message = decodedText.string ();
+  QString dxCall;
+  QString dxGrid;
+  decodedText.deCallAndGrid (dxCall, dxGrid);
   message = message.left (message.indexOf (QChar::Nbsp)); // strip appended info
   if (displayDXCCEntity && CQcall)
     // if enabled add the DXCC entity and B4 status to the end of the
     // preformated text line t1
     message = appendDXCCWorkedB4 (message, decodedText.CQersCall (), &bg, logBook, color_CQ,
                                   color_DXCC, color_NewCall);
-  appendText (message.trimmed (), bg);
+  appendText (message.trimmed (), bg, decodedText.call (), dxCall);
 }
 
 
@@ -254,3 +309,96 @@ void DisplayText::displayFoxToBeCalled(QString t, QColor bg)
 {
   appendText(t,bg);
 }
+
+namespace
+{
+  void update_selection (QTextCursor& cursor, QColor const& bg, QColor const& fg)
+  {
+    if (!cursor.isNull ())
+      {
+        QTextCharFormat format {cursor.charFormat ()};
+        if (bg.isValid ())
+          {
+            format.setBackground (bg);
+          }
+        else
+          {
+            format.clearBackground ();
+          }
+        if (fg.isValid ())
+          {
+            format.setForeground (fg);
+          }
+        else
+          {
+            format.clearForeground ();
+          }
+        cursor.mergeCharFormat (format);
+      }
+  }
+
+  void reset_selection (QTextCursor& cursor)
+  {
+    if (!cursor.isNull ())
+      {
+        // restore previous text format, we rely on the text
+        // char format at he start of the selection being the
+        // old one which should be the case
+        auto c2 = cursor;
+        c2.setPosition (c2.selectionStart ());
+        cursor.setCharFormat (c2.charFormat ());
+      }
+  }
+}
+
+void DisplayText::highlight_callsign (QString const& callsign, QColor const& bg, QColor const& fg, bool last_only)
+{
+  QTextCharFormat old_format {currentCharFormat ()};
+  QTextCursor cursor {document ()};
+  if (last_only)
+    {
+      cursor.movePosition (QTextCursor::End);
+      cursor = document ()->find (callsign, cursor
+                                  , QTextDocument::FindBackward | QTextDocument::FindWholeWords);
+      if (bg.isValid () || fg.isValid ())
+        {
+          update_selection (cursor, bg, fg);
+        }
+      else
+        {
+          reset_selection (cursor);
+        }
+    }
+  else
+    {
+      auto pos = highlighted_calls_.find (callsign);
+      if (bg.isValid () || fg.isValid ())
+        {
+          auto colours = qMakePair (bg, fg);
+          if (pos == highlighted_calls_.end ())
+            {
+              pos = highlighted_calls_.insert (callsign.toUpper (), colours);
+            }
+          else
+            {
+              pos.value () = colours; // update colours
+            }
+          while (!cursor.isNull ())
+            {
+              cursor = document ()->find (callsign, cursor, QTextDocument::FindWholeWords);
+              update_selection (cursor, bg, fg);
+            }
+        }
+      else if (pos != highlighted_calls_.end ())
+        {
+          highlighted_calls_.erase (pos);
+          QTextCursor cursor {document ()};
+          while (!cursor.isNull ())
+            {
+              cursor = document ()->find (callsign, cursor, QTextDocument::FindWholeWords);
+              reset_selection (cursor);
+            }
+        }
+    }
+  setCurrentCharFormat (old_format);
+}
diff --git a/displaytext.h b/displaytext.h
index 0e027d9eb..0f1ef01b3 100644
--- a/displaytext.h
+++ b/displaytext.h
@@ -4,6 +4,9 @@
 
 #include <QTextEdit>
 #include <QFont>
+#include <QHash>
+#include <QPair>
+#include <QString>
 
 #include "logbook/logbook.h"
 #include "decodedtext.h"
@@ -30,8 +33,10 @@ public:
   Q_SIGNAL void selectCallsign (Qt::KeyboardModifiers);
   Q_SIGNAL void erased ();
 
-  Q_SLOT void appendText (QString const& text, QColor bg = Qt::white);
+  Q_SLOT void appendText (QString const& text, QColor bg = Qt::white
+                          , QString const& call1 = QString {}, QString const& call2 = QString {});
   Q_SLOT void erase ();
+  Q_SLOT void highlight_callsign (QString const& callsign, QColor const& bg, QColor const& fg, bool last_only);
 
 protected:
   void mouseDoubleClickEvent(QMouseEvent *e);
@@ -43,6 +48,7 @@ private:
 
   QFont char_font_;
   QAction * erase_action_;
+  QHash<QString, QPair<QColor, QColor>> highlighted_calls_;
 };
 
 #endif // DISPLAYTEXT_H
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 57de7266b..2469f4c7c 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -497,6 +497,8 @@ MainWindow::MainWindow(QDir const& temp_directory, bool multiple,
       }
     });
 
+  connect (m_messageClient, &MessageClient::highlight_callsign, ui->decodedTextBrowser, &DisplayText::highlight_callsign);
+
   // Hook up WSPR band hopping
   connect (ui->band_hopping_schedule_push_button, &QPushButton::clicked
            , &m_WSPR_band_hopping, &WSPRBandHopping::show_dialog);