You are the second person to report this.
You may not believe it, but I had never used this feature. I had to load a back release and try it to see. Very handy feature. You can bet I’ll get it working again.
So the silver lining here is that I now know that graph can zoom very nicely. The latest OEM version uses a datepicker for the start and end time fields below the graph. It would be great to move that to this fork, or better yet to add a period selection box a-la grafana.
It would be great if someone wanted to contribute something like that.