diff --git a/src/Gui/ExpressionCompleter.cpp b/src/Gui/ExpressionCompleter.cpp
index 3a1bb3492b..bef42154df 100644
--- a/src/Gui/ExpressionCompleter.cpp
+++ b/src/Gui/ExpressionCompleter.cpp
@@ -820,9 +820,12 @@ void ExpressionCompleter::slotUpdate(const QString & prefix, int pos)
         std::transform(result.cbegin(),
                        result.cend(),
                        std::back_inserter(tokens),
-                       [](const std::tuple<int, int, std::string>& item) {
+                       [&](const std::tuple<int, int, std::string>& item) {
                            return std::make_tuple(
-                               get<0>(item), get<1>(item), QString::fromStdString(get<2>(item)));
+                                get<0>(item),
+                                QString::fromStdString(expr.toStdString().substr(0,get<1>(item))).size(),
+                                QString::fromStdString(get<2>(item))
+                                );
                        });
         return tokens;
     };
@@ -883,7 +886,9 @@ void ExpressionCompleter::slotUpdate(const QString & prefix, int pos)
     }
 
     // Not an unclosed string and the last character is a space
-    if (!stringing && !prefix.isEmpty() && prefix[prefixEnd-1] == QChar(32)) {
+    if (!stringing && !prefix.isEmpty() &&
+            prefixEnd > 0 && prefixEnd <= prefix.size() &&
+            prefix[prefixEnd-1] == QChar(32)) {
         if (auto itemView = popup())
             itemView->setVisible(false);
         return;
diff --git a/src/Gui/NotificationBox.cpp b/src/Gui/NotificationBox.cpp
index 4a45cf0c6d..6f0bef9e44 100644
--- a/src/Gui/NotificationBox.cpp
+++ b/src/Gui/NotificationBox.cpp
@@ -180,7 +180,7 @@ void NotificationLabel::paintEvent(QPaintEvent *ev)
 {
     QStylePainter p(this);
     QStyleOptionFrame opt;
-    opt.init(this);
+    opt.initFrom(this);
     p.drawPrimitive(QStyle::PE_PanelTipLabel, opt);
     p.end();
     QLabel::paintEvent(ev);
@@ -191,7 +191,7 @@ void NotificationLabel::resizeEvent(QResizeEvent *e)
     QStyleHintReturnMask frameMask;
     QStyleOption option;
 
-    option.init(this);
+    option.initFrom(this);
 
     if (style()->styleHint(QStyle::SH_ToolTip_Mask, &option, this, &frameMask)) {
         setMask(frameMask.region);