If $L$ is a semi-simple linear Lie algebra inside $\mathfrak{gl}(V)$ then for any element of $L$, the Jordan decomposition (semi-simple + nilpotent) inside $L$ and in $\mathfrak{gl}(V)$ coincide.
Let $F$ be an algebraically closed field, but of characteristic $2$. Then $\mathfrak{sl}(2,F)$ is not semi-simple.
Qeustion: Can we embed $\mathfrak{sl}(2,F)$ in some $\mathfrak{gl}(V)$ so that $x=\begin{bmatrix} 0 & 1\\0 & 0\end{bmatrix}$ does not remain nilpotent in $\mathfrak{gl}(V)$?
Assumptions: All vector space, representation spaces are finite dimensional, $F$ is algebraically closed,...