In LyX, how do I indent the paragraph right after an lists (itemize/enumerate) environment

This works without any ERT. Redefine itemize environment as showed int the preamble of this MWE:

\documentclass[english]{article}
\let\olditemize\itemize
\renewenvironment{itemize}
{\begin{olditemize}}
{\par
\end{olditemize}
\vspace{0.7\baselineskip}
\par}

\begin{document}
First paragraph 
\begin{itemize}
\item item 1
\item item 2
\item item 3
\end{itemize}
First paragraph  

Third paragraph 
\end{document}

Change 0.7\baselineskip if you want more space after the last item.

• Set the cursor at the end of the last item and choose Edit -> Start New Environment (Itemize) or in the context menu (right-click) (works since LyX version 2.1) or

• Insert a new item and change the text layout to --Separator-- (works since LyX version 1.6).

The solution works for all lists environments (itemize, enumerate, description) and should work as well for all other environments.

Credits go to Günter Milde who posted it in LyX users mailinglist.