add placeholder text to address field (like in sendcoins) and set focus to address field on opening messagepage or "Clear All" / consolidate gotoMessagePage() to 1 function / rename windowTitle to "Sign Message Dialog"

src/qt/bitcoingui.cpp

@@ -724,8 +724,11 @@ void BitcoinGUI::gotoSendCoinsPage()
     disconnect(exportAction, SIGNAL(triggered()), 0, 0);
 }
 
-void BitcoinGUI::gotoMessagePage()
+void BitcoinGUI::gotoMessagePage(QString addr)
 {
+    if(!addr.isEmpty())
+        messagePage->setAddress(addr);
+
 #ifdef FIRST_CLASS_MESSAGING
     messageAction->setChecked(true);
     centralWidget->setCurrentWidget(messagePage);
@@ -734,16 +737,9 @@ void BitcoinGUI::gotoMessagePage()
     disconnect(exportAction, SIGNAL(triggered()), 0, 0);
 #else
     messagePage->show();
-    messagePage->setFocus();
 #endif
 }
 
-void BitcoinGUI::gotoMessagePage(QString addr)
-{
-    gotoMessagePage();
-    messagePage->setAddress(addr);
-}
-
 void BitcoinGUI::dragEnterEvent(QDragEnterEvent *event)
 {
     // Accept only URIs