This feature is beta and only the additional setting to enable the *Unsafe Browser* is made persistent. The other settings (language, keyboard, and other additional settings) will be made persistent in Tails 4.9 (July 28).
If you use spaces or other accentuated characters, like <span class="code">àéïøů</span>, your will not be able to type your administration password again in your Tails session, unless you type single quotes <span class="code">'</span> around it.
For example, if you set the administration password: <span class="code">née entrepôt über señor</span>, you would have to type <span class="code">'née entrepôt über señor'</span>. ([[!tails_ticket 17792]])