Hi,
This problem should not happen with any well configured Linux or UNIX distribution. In fact, running PixInsight on X11 without a working compositing manager is currently deprecated, and will be disabled during the 1.8 cycle.
If you are new to Linux and have no special reason to use a particular distribution, I strongly recommend you install a recent version of Fedora or Ubuntu, with a recent version of KDE 4, GNOME 2 or GNOME 3, at your option. PixInsight works perfectly with these distributions and desktop managers.