Fix missing calendar participant + button

set_readonly() was missing, getWindowTitle() was using .options.value instead of get_value()

api/js/etemplate/Et2InputWidget/Et2InputWidget.ts

@@ -71,11 +71,13 @@ const Et2InputWidgetMixin = (superclass) =>
 			super(...args);
 
 		}
+
 		connectedCallback()
 		{
 			super.connectedCallback();
 			this.node = this.getInputNode();
 		}
+
 		set_value(new_value)
 		{
 			this.value = new_value;
@@ -86,6 +88,11 @@ const Et2InputWidgetMixin = (superclass) =>
 			return this.getValue();
 		}
 
+		set_readonly(new_value)
+		{
+			this.readonly = this.readOnly = new_value;
+		}
+
 		getValue()
 		{
 			return typeof this.serializedValue !== "undefined" ? this.serializedValue : this.modalValue;