My email service is working as it always did but my wife's (username+hername) has suddenly altered in that where she used to click once on a message to open it, she now has to double click. She does have habit of clicking things she shouldn't so it is possible she has altered a setting. (normal internet use only needs a single click so it is something peculiar to Plusnet web mail - also it's the same with either I.E. or Firefox). I've searched settings to no avail.
Somehow, "show preview pane" had become unticked. Even I might have done it when messing about. It's a funny description though, and I was used to messages always showing underneath as they all do such as hotmail, bt mail, gmail, gmx mail.
However, panic over. Also I've learned something - by double clicking then you get the message large without the inbox at the top.