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Haar measure of algebraic orbits

Let $G$ be a simple linear algebraic group acting on a projective variety $X$ through rational maps. Let $x_0\in X$ with stabilizer group $H$ and assume that $G/H$ in not compact and carries a $G$-invariant measure $\mu$. Let $z\in X$ be in the boundary of the orbit $G.x_0$ and let $U\subset X$ be an open neighborhood of $z$. Let $G(U)\subset G/H$ be the set of all $gH\in G/H$ such that $g.x_0\in U$. Is it true that $\mu(G(U))=\infty$?

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