new file mode 100644
--- /dev/null
+++ b/src/qt/qvalidatedlineedit.h
@@ -0,0 +1,27 @@
+#ifndef QVALIDATEDLINEEDIT_H
+#define QVALIDATEDLINEEDIT_H
+
+#include <QLineEdit>
+
+// Line edit that can be marked as "invalid". When marked as invalid,
+// it will get a red background until it is focused.
+class QValidatedLineEdit : public QLineEdit
+{
+    Q_OBJECT
+public:
+    explicit QValidatedLineEdit(QWidget *parent = 0);
+
+protected:
+    void focusInEvent(QFocusEvent *evt);
+
+private:
+    bool valid;
+
+public slots:
+    void setValid(bool valid);
+
+private slots:
+    void markValid();
+};
+
+#endif // QVALIDATEDLINEEDIT_H