fckg's plugin can, AFAIK, only set RTL / LTR for the whole website. it's a global configuration bit. Other editors usually have 2 buttons that set the current paragraph direction (P / div / H1, etc.)
The configuration option only sets direction for the editor, not for the whole web web site. The choices are:
nocheck: fckgLite will make no changes to the default direction setting;
dokuwiki: the current Dokuwiki language direction;
ltr: Left-to-right ;
rtl: Right-to-left.
You will not find the button you describe in Dokuwiki, unless someone has implemented it as a plugin.