improved effects signalling

ui/checkboxex.cpp

@@ -0,0 +1,12 @@
+#include "checkboxex.h"
+
+#include "project/undo.h"
+
+CheckboxEx::CheckboxEx(QWidget* parent) : QCheckBox(parent) {
+	connect(this, SIGNAL(clicked(bool)), this, SLOT(checkbox_command()));
+}
+
+void CheckboxEx::checkbox_command() {
+	CheckboxCommand* c = new CheckboxCommand(this);
+	undo_stack.push(c);
+}