Open opens the selected files/directory.
If the directory tree has the focus, this action will only work, if a Directory Command
has been configured in the preferences (see External Tools).
If the file table has the focus the file(s) will be opened in an editor.
The editor which shall be used to open a file can be configured in the Externals Tools
section of the Preferences (see External Tools).
If no editor is configured there, the internal File Editor
will be launched.
For files, you can specify a limit on the file count beyond which you will be asked
before the files are opened at once; for details refer to Open.