diff --git a/gui/libraryaddfunctiondialog.cpp b/gui/libraryaddfunctiondialog.cpp
index 941fb2fb4..d2dfb3944 100644
--- a/gui/libraryaddfunctiondialog.cpp
+++ b/gui/libraryaddfunctiondialog.cpp
@@ -4,10 +4,6 @@
 #include <QRegExp>
 #include <QValidator>
 
-#define SIMPLENAME     "[_a-zA-Z][_a-zA-Z0-9]*"            // just a name
-#define SCOPENAME      SIMPLENAME "(::" SIMPLENAME ")*"    // names with optional scope
-#define NAMES          SCOPENAME "(," SCOPENAME ")*"       // names can be separated by comma
-
 LibraryAddFunctionDialog::LibraryAddFunctionDialog(QWidget *parent) :
     QDialog(parent),
     ui(new Ui::LibraryAddFunctionDialog)
diff --git a/gui/libraryaddfunctiondialog.h b/gui/libraryaddfunctiondialog.h
index de63f1d37..465c567af 100644
--- a/gui/libraryaddfunctiondialog.h
+++ b/gui/libraryaddfunctiondialog.h
@@ -3,6 +3,10 @@
 
 #include <QDialog>
 
+#define SIMPLENAME     "[_a-zA-Z][_a-zA-Z0-9]*"            // just a name
+#define SCOPENAME      SIMPLENAME "(::" SIMPLENAME ")*"    // names with optional scope
+#define NAMES          SCOPENAME "(," SCOPENAME ")*"       // names can be separated by comma
+
 namespace Ui {
     class LibraryAddFunctionDialog;
 }
diff --git a/gui/librarydialog.cpp b/gui/librarydialog.cpp
index 037fbe8fc..a34a392c4 100644
--- a/gui/librarydialog.cpp
+++ b/gui/librarydialog.cpp
@@ -29,6 +29,20 @@
 
 // TODO: get/compare functions from header
 
+class FunctionListItem : public QListWidgetItem {
+public:
+    FunctionListItem(QListWidget *view,
+                     CppcheckLibraryData::Function *function,
+                     bool selected)
+        : QListWidgetItem(view), function(function)
+    {
+        setText(function->name);
+        setFlags(flags() | Qt::ItemIsEditable);
+        setSelected(selected);
+    }
+    CppcheckLibraryData::Function *function;
+};
+
 LibraryDialog::LibraryDialog(QWidget *parent) :
     QDialog(parent),
     ui(new Ui::LibraryDialog),
@@ -50,11 +64,7 @@ CppcheckLibraryData::Function *LibraryDialog::currentFunction()
     QList<QListWidgetItem *> selitems = ui->functions->selectedItems();
     if (selitems.count() != 1)
         return nullptr;
-    for (int row = 0; row < data.functions.size(); ++row) {
-        if (data.functions[row].name == selitems.front()->text())
-            return &data.functions[row];
-    }
-    return nullptr;
+    return dynamic_cast<FunctionListItem *>(selitems.first())->function;
 }
 
 void LibraryDialog::openCfg()
@@ -80,8 +90,10 @@ void LibraryDialog::openCfg()
             ui->buttonSave->setEnabled(false);
             ui->filter->clear();
             ui->functions->clear();
-            foreach(const struct CppcheckLibraryData::Function &function, data.functions) {
-                ui->functions->addItem(function.name);
+            for (struct CppcheckLibraryData::Function &function : data.functions) {
+                ui->functions->addItem(new FunctionListItem(ui->functions,
+                                                            &function,
+                                                            false));
             }
             ui->sortFunctions->setEnabled(!data.functions.empty());
             ui->filter->setEnabled(!data.functions.empty());
@@ -117,7 +129,7 @@ void LibraryDialog::addFunction()
             f.args.append(arg);
         }
         data.functions.append(f);
-        ui->functions->addItem(f.name);
+        ui->functions->addItem(new FunctionListItem(ui->functions, &data.functions.back(), false));
         ui->buttonSave->setEnabled(true);
         ui->sortFunctions->setEnabled(!data.functions.empty());
         ui->filter->setEnabled(!data.functions.empty());
@@ -125,6 +137,24 @@ void LibraryDialog::addFunction()
     delete d;
 }
 
+void LibraryDialog::editFunctionName(QListWidgetItem* item)
+{
+    if (ignoreChanges)
+        return;
+    QString functionName = item->text();
+    CppcheckLibraryData::Function * const function = dynamic_cast<FunctionListItem*>(item)->function;
+    if (functionName != function->name) {
+        if (QRegExp(NAMES).exactMatch(functionName)) {
+            function->name = functionName;
+            ui->buttonSave->setEnabled(true);
+        } else {
+            ignoreChanges = true;
+            item->setText(function->name);
+            ignoreChanges = false;
+        }
+    }
+}
+
 void LibraryDialog::selectFunction()
 {
     const CppcheckLibraryData::Function * const function = currentFunction();
@@ -147,17 +177,16 @@ void LibraryDialog::selectFunction()
 
 void LibraryDialog::sortFunctions(bool sort)
 {
-    if (sort)
+    if (sort) {
         ui->functions->sortItems();
-    else {
+    } else {
         ignoreChanges = true;
         CppcheckLibraryData::Function *selfunction = currentFunction();
         ui->functions->clear();
-        foreach(const struct CppcheckLibraryData::Function &function, data.functions) {
-            QListWidgetItem *item = new QListWidgetItem(ui->functions);
-            item->setText(function.name);
-            item->setSelected(selfunction == &function);
-            ui->functions->addItem(item);
+        for (struct CppcheckLibraryData::Function &function : data.functions) {
+            ui->functions->addItem(new FunctionListItem(ui->functions,
+                                                        &function,
+                                                        selfunction == &function));
         }
         if (!ui->filter->text().isEmpty())
             filterFunctions(ui->filter->text());
diff --git a/gui/librarydialog.h b/gui/librarydialog.h
index 07dfda5ba..46472e195 100644
--- a/gui/librarydialog.h
+++ b/gui/librarydialog.h
@@ -43,6 +43,7 @@ private slots:
     void addFunction();
     void changeFunction();
     void editArg();
+    void editFunctionName(QListWidgetItem*);
     void filterFunctions(QString);
     void selectFunction();
     void sortFunctions(bool);
diff --git a/gui/librarydialog.ui b/gui/librarydialog.ui
index 020796516..460bf5d11 100644
--- a/gui/librarydialog.ui
+++ b/gui/librarydialog.ui
@@ -89,7 +89,7 @@
        <item>
         <widget class="QListWidget" name="functions">
          <property name="editTriggers">
-          <set>QAbstractItemView::NoEditTriggers</set>
+          <set>QAbstractItemView::DoubleClicked</set>
          </property>
          <property name="selectionBehavior">
           <enum>QAbstractItemView::SelectRows</enum>
@@ -313,8 +313,8 @@
    <slot>editArg()</slot>
    <hints>
     <hint type="sourcelabel">
-     <x>488</x>
-     <y>580</y>
+     <x>519</x>
+     <y>575</y>
     </hint>
     <hint type="destinationlabel">
      <x>497</x>
@@ -361,8 +361,8 @@
    <slot>filterFunctions(QString)</slot>
    <hints>
     <hint type="sourcelabel">
-     <x>257</x>
-     <y>565</y>
+     <x>429</x>
+     <y>575</y>
     </hint>
     <hint type="destinationlabel">
      <x>273</x>
@@ -402,6 +402,22 @@
     </hint>
    </hints>
   </connection>
+  <connection>
+   <sender>functions</sender>
+   <signal>itemChanged(QListWidgetItem*)</signal>
+   <receiver>LibraryDialog</receiver>
+   <slot>editFunctionName(QListWidgetItem*)</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>217</x>
+     <y>104</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>235</x>
+     <y>104</y>
+    </hint>
+   </hints>
+  </connection>
  </connections>
  <slots>
   <slot>addFunction()</slot>
@@ -413,5 +429,6 @@
   <slot>saveCfg()</slot>
   <slot>selectFunction()</slot>
   <slot>sortFunctions(bool)</slot>
+  <slot>editFunctionName(QListWidgetItem*)</slot>
  </slots>
 </ui>