Equation position changing

\documentclass[10pt,a4paper,xcolor=dvipsnames,xcolor=table]{beamer}
\pdfpageattr{/Group <

>} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % PACKAGES \usepackage{mathrsfs,amsmath,amsfonts,amssymb,makeidx} \begin{document} \begin{frame} \begin{overlayarea}{\textwidth}{6cm} \[QQ=RR\]\pause \begin{itemize} \item Retarded \item \only<2>{Exp1} $A=B$\\ \only<2>{$B=C$}\pause \item $C=D$\\ \only<3>{ where { \begin{align} P&=Q \nonumber\\ Q &=0&\nonumber \end{align} } } \pause \item Exp2 \[W=U\] \end{itemize} \end{overlayarea} \end{frame} \end{document}