For copy/move operations the progress bar dialogue has input focus not the copy dialogue so if you want to overwrite an existing file there is no quick keyboard solution and you have to use a mouse to change the input focus and select Overwrite and possibly "Apply to All". If the user is prompted for a response then the input focus should be on the box they respond to, not the progress bar. A keyboard user who knows their way around a program is usually more efficient than a mouse user.
KDE 5 does not have a progress bar dialogue and the "File already exists" dialog is instantly focused. Btw. both dialogs are not part of Krusader but KF5/KDELibs. And you should always be able to focus another dialog/window with ALT+Tab.
(In reply to Alex Bikadorov from comment #1) > KDE 5 does not have a progress bar dialogue and the "File already exists" > dialog is instantly focused. Btw. both dialogs are not part of Krusader but > KF5/KDELibs. > > And you should always be able to focus another dialog/window with ALT+Tab. Thanks Alex. So it looks like a KDE in Unity/gnome issue which I'll just have to live with.