Improve display for long user and group names

Long user and group names are not rendered completely, as per the attached screenshot. A mouseover will display the complete text but it may not be the most intuitive and user-friendly UI for instances with a lot of long user and group names, specially if the trailing part of them is the one that distinguishes one from the rest.
Would be helpful to have a better UI where these names can be completely viewed either by having a flexible dropdown that takes the longest name into account to set column width automatically or a control that allows users to expand to view the rest of the name.