implemented undos for effect fields that aren't keyframed

ui/fontcombobox.cpp

@@ -4,4 +4,18 @@
 
 FontCombobox::FontCombobox(QWidget* parent) : ComboBoxEx(parent) {
 	addItems(QFontDatabase().families());
+
+	value = currentText();
+
+	connect(this, SIGNAL(currentTextChanged(QString)), this, SLOT(updateInternals()));
+}
+
+const QString& FontCombobox::getPreviousValue() {
+	return previousValue;
+}
+
+void FontCombobox::updateInternals() {
+	qDebug() << "h";
+	previousValue = value;
+	value = currentText();
 }