Hi, since the April 2018 release, it is not possible to sort A-Z on a chart axis, only Z-A. When clicking A-Z on the dropdown elipses, nothing happens. It is possible to sort by a measure but not A...
Luckily we have a yammer group for all the Power BI users at my current client and also a dedicated support team for Power BI. I posted something about this "changing behavior" and also updated the support team, Until now we had just one support case that could be closed very fast, now we are waiting for the May magic :-)