Thank you Licquorice, that's what I'll have to do - use a different browser. I was trying to stick with the edge layout that I spent 7 hours (!) discussing with BT back in October but enough is enough. In the olden days, innovations were well and truly tested before they were rolled out to customers but no longer, sadly.
We are trying to reproduce this preview issue. If at all possible, can you send me a screenshot so we can check which scrollbars are present on the screen and which preview mode (above or right) is being used. We are working on the correcting the selection option from the move option. You may not be able to select some sub-folders (of the current folder) when moving mail, but you can drag-and-drop the emails onto the desired folder in the expanded list in the left-hand column.
You can send me this screenshot by private message or else post it up on this thread. If you post it on this thread make sure there is no personal identifiable information in the image.
Thank you DanielS but as viewing emails has been so difficult since the changes in October, I am making alternative arrangements.