Like fools we have been upgrading our desktops to Windows 10.
There a small annoying bug in the webmail when using Windws 10 Edge browser, if you have any text selected in the preview pane, then clicking on another email in the content pane, the preview pane no longer shows anything (i.e. empty).
The only way clear this bug is to either refresh the browser or click on a folder in the folder pane. For people who do lot of cut & pasting from emails it is extremely annoying!
Windows 10, MS Edge, Smartermail 15.1.6005 under IIS