enable/disable/add/remove groundwork done

src/qt/qtclasses.h

@@ -61,6 +61,10 @@
 class ExtendedCheckBox : public QCheckBox {
 	Q_OBJECT	
 public:
+	//c++11: this inherits all parent's constructors unconditionally
+	using QCheckBox::QCheckBox;
+	//alternative being calling parent ctor directly after declaring child ctor:
+	//B(int x) : A(x) { }
 	bool event(QEvent* ev) override;
 };