Need to undo the last operation，but Cmmand+Z not working，is this a bug?
Undo is indeed not granular enough a bit slow at the moment, we’re not too happy with it ourselves either. We need to make quite a big change to fix it, the plan is to dive onto this the moment we have shipped the images and attachment support (which should be soon now). Thanks for reporting the issues and thank you for your patience.
Yes, the undo bug is very annoying, looking forward to fix it. Thanks