The default ClassyTk file save dialog contains two listboxes. The left one contains the subdirectories in the current directory. The right one contains the files already present. Double clicking on a filename will select this name, and the file with this name will be overwritten. Single clicking will put the name in the 'File' entry under the listboxes, where it can be edited, before clicking the Select button, ot pressing 'Enter'. The top entry labeled 'Filter' can be used to limit the listing of files to those matching the filter.