Using this code, how to make fill lines solid (different than border dashed line)
\documentclass{beamer}
\beamertemplatenavigationsymbolsempty
\usepackage{tikz}
\usetikzlibrary{patterns}
\usepackage{pgfplots}
\begin{document}
\begin{frame}
\frametitle{}
\begin{tikzpicture}
\draw[blue, thin, densely dashed, pattern=north east lines, pattern color=red] (0,0) rectangle (2,2);
\end{tikzpicture}
\end{frame}
\end{document}