After starting a new text or folder comparison session, you see 2 or 3 empty panes and above each pane the edit field to enter file or folder name.
By default setting Load file/folder before comparison is not enabled at Options - Configuration - Application Layout.
So after directly entering the file/folder name or browsing to the file/folder with the appropriate button, the pane below still does not display file/folder contents although file/folder is already entered/selected. The 2 or 3 panes show only file/folder contents after executing the comparison with a click on green arrow button.
The behavior changes with configuration setting Load file/folder before comparison being enabled. Now after entering/selecting a file/folder, the pane below immediately displays the file/folder contents. So file/folder is read by UltraCompare already before making the comparison.
Reading file/folder before comparison is no problem for small local files/folders as the time required for reading and displaying file/folder contents is short. If you want to see file/folder contents before running the comparison, then enable this configuration setting. But for large files/folders or remote files/folders (loaded via FTP/FTPS/SFTP) reading and displaying before comparison is no good idea as you might imagine because the time required for this reading and displaying process is long.
Best regards from an UC/UE/UES for Windows user from Austria