diff --git a/src/resources/markdown_template.js b/src/resources/markdown_template.js
index bbc021ca..e0658979 100644
--- a/src/resources/markdown_template.js
+++ b/src/resources/markdown_template.js
@@ -1622,7 +1622,7 @@ var htmlToText = function(identifier, id, timeStamp, html) {
     content.htmlToTextCB(identifier, id, timeStamp, markdown);
 };
 
-var performSmartLivePreview = function(lang, text) {
+var performSmartLivePreview = function(lang, text, hints, isRegex) {
     if (previewDiv.style.display == 'none') {
         return;
     }
@@ -1632,7 +1632,35 @@ var performSmartLivePreview = function(lang, text) {
     }
 
     // PlantUML.
-    var targetNode = findNodeWithText(previewDiv, new RegExp(text));
+    var targetNode = null;
+    if (hints.indexOf('id') >= 0) {
+        // isRegex is ignored.
+        targetNode = findNodeWithText(previewDiv,
+                                      text,
+                                      function (node, text) {
+                                          if (!node.id) {
+                                              return false;
+                                          }
+
+                                          return node.id == text;
+                                      });
+    } else {
+        if (isRegex) {
+            var nodeReg = new RegExp(text);
+            targetNode = findNodeWithText(previewDiv,
+                                          text,
+                                          function(node, text) {
+                                              return nodeReg.test(node.textContent);
+                                          });
+        } else {
+            targetNode = findNodeWithText(previewDiv,
+                                          text,
+                                          function(node, text) {
+                                              return node.textContent.indexOf(text) >= 0;
+                                          });
+        }
+    }
+
     if (!targetNode) {
         return;
     }
@@ -1665,17 +1693,17 @@ var performSmartLivePreview = function(lang, text) {
         if (trect.height >= vrect.height) {
             dy = trect.top;
         } else {
-            dy = trect.top - (vrect.height - trect.width) / 2;
+            dy = trect.top - (vrect.height - trect.height) / 2;
         }
     }
 
     window.scrollBy(dx, dy);
 }
 
-var findNodeWithText = function(node, reg) {
+var findNodeWithText = function(node, text, isMatched) {
     var children = node.children;
     if (children.length == 0) {
-        if (reg.test(node.textContent)) {
+        if (isMatched(node, text)) {
             return node;
         } else {
             return null;
@@ -1683,13 +1711,13 @@ var findNodeWithText = function(node, reg) {
     }
 
     for (var i = 0; i < children.length; ++i) {
-        var ret = findNodeWithText(children[i], reg);
+        var ret = findNodeWithText(children[i], text, isMatched);
         if (ret) {
             return ret;
         }
     }
 
-    if (reg.test(node.textContent)) {
+    if (isMatched(node, text)) {
         return node;
     }
 
diff --git a/src/vdocument.cpp b/src/vdocument.cpp
index ba03a449..cc904d6c 100644
--- a/src/vdocument.cpp
+++ b/src/vdocument.cpp
@@ -203,9 +203,13 @@ void VDocument::previewCodeBlockCB(int p_id, const QString &p_lang, const QStrin
     emit codeBlockPreviewReady(p_id, p_lang, p_html);
 }
 
-void VDocument::performSmartLivePreview(const QString &p_lang, const QString &p_text)
+void VDocument::performSmartLivePreview(const QString &p_lang,
+                                        const QString &p_text,
+                                        const QString &p_hints,
+                                        bool p_isRegex)
 {
     if (!p_text.isEmpty()) {
-        emit requestPerformSmartLivePreview(p_lang, p_text);
+        qDebug() << "performSmartLivePreview" << p_lang << p_text << p_hints << p_isRegex;
+        emit requestPerformSmartLivePreview(p_lang, p_text, p_hints, p_isRegex);
     }
 }
diff --git a/src/vdocument.h b/src/vdocument.h
index 08fb272e..b9cc90c0 100644
--- a/src/vdocument.h
+++ b/src/vdocument.h
@@ -75,7 +75,10 @@ public:
 
     void muteWebView(bool p_muted);
 
-    void performSmartLivePreview(const QString &p_lang, const QString &p_text);
+    void performSmartLivePreview(const QString &p_lang,
+                                 const QString &p_text,
+                                 const QString &p_hints,
+                                 bool p_isRegex);
 
 public slots:
     // Will be called in the HTML side
@@ -194,7 +197,10 @@ signals:
 
     void requestMuted(bool p_muted);
 
-    void requestPerformSmartLivePreview(const QString &p_lang, const QString &p_text);
+    void requestPerformSmartLivePreview(const QString &p_lang,
+                                        const QString &p_text,
+                                        const QString &p_hints,
+                                        bool p_isRegex);
 
 private:
     QString m_toc;
diff --git a/src/vlivepreviewhelper.cpp b/src/vlivepreviewhelper.cpp
index d7a06344..240fc8a2 100644
--- a/src/vlivepreviewhelper.cpp
+++ b/src/vlivepreviewhelper.cpp
@@ -535,6 +535,10 @@ void VLivePreviewHelper::performSmartLivePreview()
     }
 
     const CodeBlockPreviewInfo &cb = m_codeBlocks[m_cbIndex];
+    if (!cb.hasImageData()) {
+        return;
+    }
+
     const VCodeBlock &vcb = cb.codeBlock();
     const QTextBlock block = m_editor->textCursorW().block();
     if (block.blockNumber() <= vcb.m_startBlock
@@ -542,10 +546,13 @@ void VLivePreviewHelper::performSmartLivePreview()
         return;
     }
 
-    QString keyword;
+    QString keyword, hints;
+    bool isRegex = false;
     if (vcb.m_lang == "puml" && m_plantUMLMode == PlantUMLMode::LocalPlantUML) {
-        keyword = VPlantUMLHelper::keywordForSmartLivePreview(block.text());
+        keyword = VPlantUMLHelper::keywordForSmartLivePreview(block.text(),
+                                                              hints,
+                                                              isRegex);
     }
 
-    m_document->performSmartLivePreview(vcb.m_lang, keyword);
+    m_document->performSmartLivePreview(vcb.m_lang, keyword, hints, isRegex);
 }
diff --git a/src/vplantumlhelper.cpp b/src/vplantumlhelper.cpp
index 108fb6f7..cb59230a 100644
--- a/src/vplantumlhelper.cpp
+++ b/src/vplantumlhelper.cpp
@@ -189,37 +189,269 @@ QByteArray VPlantUMLHelper::process(const QString &p_format, const QString &p_te
     return out;
 }
 
-static bool tryClassDiagram(QString &p_keyword)
+static bool tryClassDiagram(QString &p_keyword, QString &p_hints, bool &p_isRegex)
 {
-    {
+    Q_UNUSED(p_isRegex);
+
     // class ABC #Pink {
-    QRegExp classDef1("class\\s*(\\w+)\\s*.*");
+    static QRegExp classDef1("^\\s*(?:class|(?:abstract(?:\\s+class)?)|interface|annotation|enum)\\s*"
+                             "(?!class)(\\w+)\\s*.*");
     if (classDef1.indexIn(p_keyword) >= 0) {
         p_keyword = classDef1.cap(1);
+        p_hints = "id";
         return true;
     }
-    }
 
-    {
     // class "ABC DEF" as AD #Pink {
-    QRegExp classDef2("class\\s*\"([^\"]+)\"\\s*.*");
+    static QRegExp classDef2("^\\s*(?:class|(?:abstract(?:\\s+class)?)|interface|annotation|enum)\\s*"
+                             "\"([^\"]+)\"\\s*(?:\\bas (\\w+))?.*");
     if (classDef2.indexIn(p_keyword) >= 0) {
-        p_keyword = classDef2.cap(1);
+        if (classDef2.cap(2).isEmpty()) {
+            p_keyword = classDef2.cap(1);
+        } else {
+            p_keyword = classDef2.cap(2);
+        }
+        p_hints = "id";
         return true;
     }
+
+    // class01 "1" *-- "many" class02 : contains 4 >
+    static QRegExp relation("^\\s*(?:(\\w+)|\"([^\"]+)\")\\s+"
+                            "(?:\"[^\"]+\"\\s+)?"
+                            "(?:<\\||[*o<#x}+^])?" "(?:-+|\\.+)" "(?:\\|>|[*o>#x{+^])?\\s+"
+                            "(?:\"[^\"]+\"\\s+)?"
+                            "(?:(\\w+)|\"([^\"]+)\")\\s*"
+                            "(?::(.+))?");
+    if (relation.indexIn(p_keyword) >= 0) {
+        QString note(relation.cap(5));
+        if (note.isEmpty()) {
+            QString class2 = relation.cap(3);
+            if (class2.isEmpty()) {
+                class2 = relation.cap(4);
+            }
+
+            p_keyword = class2;
+            p_hints = "id";
+        } else {
+            p_keyword = note.trimmed();
+        }
+
+        return true;
+    }
+
+    // {static} field : String
+    bool containsModifier = false;
+    static QRegExp modifier("\\{(?:static|abstract|classifier)\\}");
+    if (modifier.indexIn(p_keyword) >= 0) {
+        containsModifier = true;
+        p_keyword.remove(modifier);
+    }
+
+    // + field
+    static QRegExp member("^\\s*[-#~+]\\s*(.*)");
+    if (member.indexIn(p_keyword) >= 0) {
+        p_keyword = member.cap(1).trimmed();
+        return true;
+    } else if (containsModifier) {
+        p_keyword = p_keyword.trimmed();
+        return true;
+    }
+
+    // note left on link: message
+    // note left on link
+    // node on link: message
+    // MUST before next rule "note".
+    static QRegExp note4("^\\s*note\\s+(?:(?:left|top|right|bottom)\\s+)?"
+                         "on\\s+link"
+                         "[^:]*"
+                         "(?::(.*))?");
+    if (note4.indexIn(p_keyword) >= 0) {
+        p_keyword = note4.cap(1).trimmed();
+        return true;
+    }
+
+    // note top of Object: message
+    // note top of Object
+    // note top: message
+    static QRegExp note("^\\s*note\\s+(?:left|top|right|bottom)"
+                        "(?:\\s+of\\s+(\\w+))?\\s*"
+                        "(?::(.*))?");
+    if (note.indexIn(p_keyword) >= 0) {
+        p_keyword = note.cap(2).trimmed();
+        if (p_keyword.isEmpty()) {
+            p_keyword = note.cap(1);
+            if (!p_keyword.isEmpty()) {
+                p_hints = "id";
+            }
+        }
+
+        return true;
+    }
+
+    // note "a floating note" as N1
+    // note as N1
+    static QRegExp note2("^\\s*note\\s+(?:\"([^\"]*)\"\\s+)?as\\s+\\w+\\s*");
+    if (note2.indexIn(p_keyword) >= 0) {
+        p_keyword = note2.cap(1);
+        return true;
+    }
+
+    // end note
+    static QRegExp note3("^\\s*end note\\s*$");
+    if (note3.indexIn(p_keyword) >= 0) {
+        p_keyword.clear();
+        return true;
     }
 
     return false;
 }
 
-QString VPlantUMLHelper::keywordForSmartLivePreview(const QString &p_text)
+static bool tryCommonElements(QString &p_keyword, QString &p_hints, bool &p_isRegex)
+{
+    Q_UNUSED(p_isRegex);
+    Q_UNUSED(p_hints);
+
+    // List.
+    // ** list
+    // # list
+    static QRegExp listMark("^\\s*(?:\\*+|#+)\\s+(.+)$");
+    if (listMark.indexIn(p_keyword) >= 0) {
+        p_keyword = listMark.cap(1).trimmed();
+        return true;
+    }
+
+    // Words in quotes.
+    // cmf("abc")
+    static QRegExp quote("^[^\"]*\"([^\"]+)\"[^\"]*$");
+    if (quote.indexIn(p_keyword) >= 0) {
+        p_keyword = quote.cap(1).trimmed();
+        return true;
+    }
+
+    return false;
+}
+
+static bool tryActivityDiagram(QString &p_keyword, QString &p_hints, bool &p_isRegex)
+{
+    Q_UNUSED(p_isRegex);
+    Q_UNUSED(p_hints);
+
+    // Activity. (Do not support color.)
+    // :Hello world;
+    // :Across multiple lines
+    static QRegExp activity1("^\\s*:(.+)\\s*$");
+    if (activity1.indexIn(p_keyword) >= 0) {
+        p_keyword = activity1.cap(1).trimmed();
+        if (!p_keyword.isEmpty()) {
+            QChar ch = p_keyword[p_keyword.size() - 1];
+            if (ch == ';' || ch == '|' || ch == '<' || ch == '>'
+                || ch == '/' || ch == ']' || ch == '}') {
+                p_keyword = p_keyword.left(p_keyword.size() - 1);
+            }
+        }
+
+        return true;
+    }
+
+    // Activity.
+    // multiple lines;
+    static QRegExp activity2("^\\s*(.+)[;|<>/\\]}]\\s*$");
+    if (activity2.indexIn(p_keyword) >= 0) {
+        p_keyword = activity2.cap(1).trimmed();
+        return true;
+    }
+
+    // start, stop, end, endif, repeat, fork, fork again, end fork, },
+    // detach
+    static QRegExp start("^\\s*(?:start|stop|end|endif|repeat|"
+                         "fork(?:\\s+again)?|end\\s+fork|\\}|detach)\\s*$");
+    if (start.indexIn(p_keyword) >= 0) {
+        p_keyword.clear();
+        return true;
+    }
+
+    // Conditionals.
+    // if (Graphviz) then (yes)
+    // else if (Graphviz) then (yes)
+    static QRegExp conIf("^\\s*(?:else)?if\\s+\\(([^\\)]+)\\)\\s+then(?:\\s+\\([^\\)]+\\))?\\s*$");
+    if (conIf.indexIn(p_keyword) >= 0) {
+        p_keyword = conIf.cap(1).trimmed();
+        return true;
+    }
+
+    // else (no)
+    static QRegExp conElse("^\\s*else(?:\\s+\\(([^\\)]+)\\))?\\s*$");
+    if (conElse.indexIn(p_keyword) >= 0) {
+        p_keyword = conElse.cap(1).trimmed();
+        return true;
+    }
+
+    // Repeat loop.
+    // repeat while (more data?)
+    static QRegExp repeat("^\\s*repeat\\s+while\\s+\\(([^\\)]+)\\)\\s*$");
+    if (repeat.indexIn(p_keyword) >= 0) {
+        p_keyword = repeat.cap(1).trimmed();
+        return true;
+    }
+
+    // while (check?) is (not empty)
+    static QRegExp whileLoop("^\\s*while\\s+\\(([^\\)]+)\\)(?:\\s+is\\s+\\([^\\)]+\\))?\\s*$");
+    if (whileLoop.indexIn(p_keyword) >= 0) {
+        p_keyword = whileLoop.cap(1).trimmed();
+        return true;
+    }
+
+    // endwhile (empty)
+    static QRegExp endWhile("^\\s*endwhile(?:\\s+\\(([^\\)]+)\\))?\\s*$");
+    if (endWhile.indexIn(p_keyword) >= 0) {
+        p_keyword = endWhile.cap(1).trimmed();
+        return true;
+    }
+
+    // partition Running {
+    static QRegExp partition("^\\s*partition\\s+(\\w+)\\s+\\{\\s*$");
+    if (partition.indexIn(p_keyword) >= 0) {
+        p_keyword = partition.cap(1).trimmed();
+        return true;
+    }
+
+    // |Swimlane1|
+    // |#Pink|Swimlane1|
+    static QRegExp swimline("^\\s*(?:\\|[^\\|]+)?\\|([^|]+)\\|\\s*$");
+    if (swimline.indexIn(p_keyword) >= 0) {
+        p_keyword = swimline.cap(1).trimmed();
+        return true;
+    }
+
+    return false;
+}
+
+QString VPlantUMLHelper::keywordForSmartLivePreview(const QString &p_text,
+                                                    QString &p_hints,
+                                                    bool &p_isRegex)
 {
     QString kw = p_text.trimmed();
     if (kw.isEmpty()) {
         return kw;
     }
 
-    if (tryClassDiagram(kw)) {
+    p_isRegex = false;
+
+    qDebug() << "tryClassDiagram" << kw;
+
+    if (tryClassDiagram(kw, p_hints, p_isRegex)) {
+        return kw;
+    }
+
+    qDebug() << "tryActivityDiagram" << kw;
+
+    if (tryActivityDiagram(kw, p_hints, p_isRegex)) {
+        return kw;
+    }
+
+    qDebug() << "tryCommonElements" << kw;
+
+    if (tryCommonElements(kw, p_hints, p_isRegex)) {
         return kw;
     }
 
diff --git a/src/vplantumlhelper.h b/src/vplantumlhelper.h
index 12ab7572..77f1c6d3 100644
--- a/src/vplantumlhelper.h
+++ b/src/vplantumlhelper.h
@@ -23,7 +23,9 @@ public:
 
     static QByteArray process(const QString &p_format, const QString &p_text);
 
-    static QString keywordForSmartLivePreview(const QString &p_text);
+    static QString keywordForSmartLivePreview(const QString &p_text,
+                                              QString &p_hints,
+                                              bool &p_isRegex);
 
 signals:
     void resultReady(int p_id,