It is just a minor UI bug, but still worth being fixed. It concerns the filename displayed in the status frame during defraggmentation.
Whenever there is an ampersand (&) in the filename or path (which is perfectly valid in Windows), the displaying item (whatever it is: static, edit, ???) interprets the ampersand sign as marking an accelerator (as it is done eg. in menu items). Thus it omits the ampersand and underscores the following character instead.
Don't know how to fix that, since I don't know what kind of display widgets are in use here. But I'm sure the devs know, what to do.