There are a few Folder Diff Window commands that are only in the Menu and not on the Toolbar.
File | Reload
Force a rescan the folders. This is useful if you have automatic reloading turned off in the Options Dialog.
View | Shortcut Details...
On Windows, this command raises the Shortcut Details dialog on the selected row. For each shortcut this dialog shows the target pathname, associated icon, description, working directory, and any command line arguments. For shortcut pairs that have file or folder targets, this dialog contains a button to open a file or folder window to compare them.
View | Symlink Details...
On Linux and Mac, this command raises the Symlink Details dialog on the selected row. For each symlink this dialog shows the target pathname.
View | Show Errors
Show/Hide items that had a filesystem error of some type.
Double-click on an error row to see the error message.