diff --git a/src/app.cpp b/src/app.cpp
index 6d65ba6..1a100f6 100644
--- a/src/app.cpp
+++ b/src/app.cpp
@@ -555,7 +555,6 @@ void App::updateOutputContainer(Wt::Json::Object conversation) {
     auto containerLayout = (Wt::WVBoxLayout*)contentContainer_->layout();
     auto outputLayoutItem = containerLayout->itemAt(1);
     auto outputContainer = (Wt::WContainerWidget*)outputLayoutItem->widget();
-    outputContainer->clear();
     outputContainer->setOverflow(Wt::Overflow::Auto);
     renderChatLines(conversation, outputContainer);
 }
@@ -574,20 +573,28 @@ void App::renderChatLines(Wt::Json::Object conversation, Wt::WContainerWidget* o
 void App::renderChatLine(Wt::Json::Object &line, Wt::Json::Object conversation, Wt::WContainerWidget* outputContainer) {
     std::string writer = getChatLineWriter(line, conversation);
     Wt::WWebWidget* item;
+    auto id = (std::string)line["id"];
+    for (const auto widget: outputContainer->children()) {
+        if (widget->attributeValue("dummy") == id) {
+            return;
+        }
+    }
     if ((std::string)line["type"] == "text") {
-        item = createTextElement(writer, (std::string)line["string"], outputContainer);
+        item = createTextElement(writer, (std::string)line["string"], outputContainer, id);
     } else if ((std::string)line["type"] == "image") {
-        item = createImageElement(line, writer, outputContainer);
+        item = createImageElement(line, writer, outputContainer, id);
     } else {
         item = new Wt::WText("");
     }
     item->setInline(false);
 }
 
-Wt::WWebWidget* App::createTextElement(const std::string& writer, const std::string& text, Wt::WContainerWidget* outputContainer) {
+Wt::WWebWidget* App::createTextElement(const std::string& writer, const std::string& text, Wt::WContainerWidget* outputContainer, std::string id) {
     std::string outputText = replaceSmileys(text);
     Wt::WString output = Wt::WString("<b>{1}</b>: {2}").arg(writer).arg(outputText);
-    return outputContainer->addNew<Wt::WText>(output);
+    auto line = outputContainer->addNew<Wt::WText>(output);
+    line->setAttributeValue("dummy", id);
+    return line;
 }
 
 void App::createImprintContainer(Wt::WVBoxLayout *containerLayout) {
@@ -637,7 +644,7 @@ void App::createImprintContainer(Wt::WVBoxLayout *containerLayout) {
     });
 }
 
-Wt::WWebWidget* App::createImageElement(Wt::Json::Object& line, const std::string& writer, Wt::WContainerWidget* outputContainer) {
+Wt::WWebWidget* App::createImageElement(Wt::Json::Object& line, const std::string& writer, Wt::WContainerWidget* outputContainer, std::string id) {
     Wt::Json::Object imageDescription = line["image"];
     auto imageLineItem = outputContainer->addNew<Wt::WContainerWidget>();
     auto outputText = Wt::WString("<b>{1}:</b>&nbsp;").arg(writer);
@@ -649,6 +656,7 @@ Wt::WWebWidget* App::createImageElement(Wt::Json::Object& line, const std::strin
         std::vector<unsigned char>(imageBlob.begin(), imageBlob.end()));
     image->setImageLink(Wt::WLink(imageResource));
     image->resize(Wt::WLength((int)imageDescription["width"], Wt::LengthUnit::Pixel), Wt::WLength((int)imageDescription["height"], Wt::LengthUnit::Pixel));
+    imageLineItem->setAttributeValue("dummy", id);
     return imageLineItem;
 }
 
diff --git a/src/app.h b/src/app.h
index 252e88b..35b11b8 100644
--- a/src/app.h
+++ b/src/app.h
@@ -182,8 +182,8 @@ private:
     std::string buildApiUrl(const std::string &userIP);
     std::string getUserIP();
     Magick::Image scaleImage(const Magick::Image &originalImage, int maxSize) const;
-    Wt::WWebWidget *createImageElement(Wt::Json::Object &line, const std::string &writer, Wt::WContainerWidget *outputContainer);
-    Wt::WWebWidget *createTextElement(const std::string &writer, const std::string &text, Wt::WContainerWidget *outputContainer);
+    Wt::WWebWidget *createImageElement(Wt::Json::Object &line, const std::string &writer, Wt::WContainerWidget *outputContainer, std::string id);
+    Wt::WWebWidget *createTextElement(const std::string &writer, const std::string &text, Wt::WContainerWidget *outputContainer, std::string id);
     void createImprintContainer(Wt::WVBoxLayout *containerLayout);
     Wt::WContainerWidget *setupSearchButton(Wt::WVBoxLayout *contentLayout);
     void restoreSearchFields(Wt::WContainerWidget *searchResultContainer, Wt::WLineEdit *userNameEdit, Wt::WSpinBox *minAgeEdit, Wt::WSpinBox *maxAgeEdit, Wt::WContainerWidget *countryDropDownContainer, Wt::WContainerWidget *gendersDropDownContainer, Wt::WPushButton *countryOpenList, Wt::WPushButton *gendersOpenList);
diff --git a/src/broadcast.cpp b/src/broadcast.cpp
index 12506dd..5001558 100644
--- a/src/broadcast.cpp
+++ b/src/broadcast.cpp
@@ -3,6 +3,7 @@
 #include <Wt/WAny.h>
 #include <Wt/Json/Array.h>
 #include <Wt/Json/Serializer.h>
+#include <Wt/Auth/HashFunction.h>
 #include <iostream>
 #include <sstream>
 #include <vector>
@@ -643,12 +644,22 @@ Broadcast::Message::Message(std::string fromSessionId_, Wt::WString message_):
         fromSessionId(fromSessionId_),
         sendType("text"),
         message(message_) {
+    auto timestamp = std::time(nullptr);
+    auto combinedString = std::to_string(timestamp) + fromSessionId_;
+    Wt::Auth::SHA1HashFunction hashObj;
+    auto hash = hashObj.compute(combinedString, "salt");
+    messageId = Wt::WString(hash);
     sendTime = Wt::WDateTime::currentDateTime();
 }
 
 Broadcast::Message::Message(std::string fromSessionId_, std::shared_ptr<Magick::Image> image_):
         fromSessionId(fromSessionId_),
         sendType("image") {
+    auto timestamp = std::time(nullptr);
+    auto combinedString = std::to_string(timestamp) + fromSessionId_;
+    Wt::Auth::SHA1HashFunction hashObj;
+    auto hash = hashObj.compute(combinedString, "salt");
+    messageId = Wt::WString(hash);
     sendTime = Wt::WDateTime::currentDateTime();
     Magick::Blob imageBlob;
     image_->write(&imageBlob);
@@ -665,6 +676,7 @@ Wt::Json::Object Broadcast::Message::json() {
     json["type"] = Wt::Json::Value(sendType);
     json["string"] = Wt::Json::Value(message);
     json["image"] = Wt::Json::Value(image);
+    json["id"] = Wt::Json::Value(messageId);
     return json;
 }
 
diff --git a/src/broadcast.h b/src/broadcast.h
index 7de4168..75da10a 100644
--- a/src/broadcast.h
+++ b/src/broadcast.h
@@ -55,6 +55,7 @@ public:
         std::string sendType;
         Wt::WDateTime sendTime;
         Wt::WString message;
+        Wt::WString messageId;
         Wt::Json::Object image;
         Wt::Json::Object json();
         void setNewSesionId(std::string oldSessionId, std::string newSessionId);