When I create a new GL Journal header and select an organization, it populates PERIOD correctly and when I change ACCOUNT DATE, it updates PERIOD correctly. However, when I change accounting schema in the Journal header, PERIOD gets removed and there are no periods to be selected. Only after changing ACCOUNT DATE to some other date will PERIOD be re-derived. To simulate this scenario, I have created a second accounting schema called "2nd schema" in Carlos' demo system https://demo.globalqss.com/webui/index.zul so you'll be able to simulate it there.
The other thing that would be nice here is if a callout would update journal header CURRENCY based on Accounting Schema CURRENCY.