Added:
  right click on filename (under Offline) brings up "Close file" option;
  automatic creation of TEMP folder (under Offline);
  right click on Groups folder brings up "Make new group" option
    which brings up a text dialog requesting a group name, which must
    be a new name;
  right click on a group name brings up "Delete group" and "Draw" options,
    "Delete group" does just that, while "Draw" automatically creates a
    new canvas divided into #pads = #histograms in the group and draws 
    the histograms one per pad;
  right click on a histogram brings up the context menu with added option
    "Add to group", which in turn brings up the list of existing groups