add 2 comments to transactionview.cpp to ensure no one moves setPlaceholderText to the XML file (after this all parts in the code that use setPlaceholderText have this comment

src/qt/transactionview.cpp

@@ -81,12 +81,14 @@ TransactionView::TransactionView(QWidget *parent) :
 
     addressWidget = new QLineEdit(this);
 #if QT_VERSION >= 0x040700
+    /* Do not move this to the XML file, Qt before 4.7 will choke on it */
     addressWidget->setPlaceholderText(tr("Enter address or label to search"));
 #endif
     hlayout->addWidget(addressWidget);
 
     amountWidget = new QLineEdit(this);
 #if QT_VERSION >= 0x040700
+    /* Do not move this to the XML file, Qt before 4.7 will choke on it */
     amountWidget->setPlaceholderText(tr("Min amount"));
 #endif
 #ifdef Q_WS_MAC