So let $D\subseteq \mathbb{C}^n$ be a **bounded** connected open set with a transitive action of its group of biholomorphisms (which we denote by $Hol(D)$). Note that **I'm not** assuming that $D$ is symmetric. We thus have that $D$ is "homeomorphic" to $Hol(D)/K$ where $K=Stab(d_0)$ for some $d_0\in D$.

In the special case where $Hol(D)$ is a real Lie group and that $K$ is a maximal compact of $Hol(D)$ then by a theorem of Elie Cartan we have that $Hol(D)/K$ is homeomoprphic to $\mathbb{R}^m$ and thus contractible.

Under my assumptions:

(1) Is $Hol(D)$ always a Lie group?

(2) Is $K$ always a maximal compact?

(3) In general is $D$ always contractible (or simply connected)?