Kate Text Editor
F7 Command Line
internal command line
text entry at the bottom of the editor area; to show it select View → Switch to Command Line or use the shortcut (default is F7).
To execute a command, type the command then press the return key.
If you entered the command line by pressing F7 it will automatically hide after a few seconds. To clear the message and enter a new command, press F7 again.
list of all available commands issue help list
help list help <command>
commands are provided by the editor component, and allow you to configure the active document and view only.
Open File Dialog
Kate does not use its own internal open file dialog. If you run Kate with KDE window manager then Kate should use the KDE file open dialog which offers configurable options like "show file extension" or allowing you to sort by file extension. If Kate is installed on a non-KDE system such as a Ubuntu system or Mint system then the GTK very limited "sucky" file dialog is used. The GTK dialog is total crap and lacks many useful features. You can't filter the file view to do things such as show only text files, you can't sort by file extension, and you cant see image thumbnails. There does not seem to be a way to not use the GTK File Chooser under a GNOME, Cinnamon or XFCE desktop. GTKFileChooser just sucks.