fix calendar.edit wont open, caused by new hidden attribute:

- parent can be undefined
- typo parent.getArr(a)yMgr()
- parseBoolExpression() does NOT support boolean values
- returning null gives errors later on, commented it out for now :(

api/js/etemplate/et2_core_arrayMgr.ts

@@ -349,8 +349,13 @@ export class et2_arrayMgr
 		return _ident;
 	}
 
-	parseBoolExpression(_expression : string)
+	parseBoolExpression(_expression : string|number|boolean|undefined)
 	{
+		if (typeof _expression === "boolean")
+		{
+			return _expression;
+		}
+
 		if(typeof _expression === "undefined" || _expression === null)
 		{
 			return false;