that's also a known "bug". I forgot to mention it because I am rarely using the GUI these days.
there are several ways to startup your processes with svipc, but one convenient way is just to fork the main process: this way, you get everything initialized and all children in sync. One problem of this approach is that if you have some plot window opened when you fork, you also fork the X poll stuff, and this is bad (leads to a crash). The solution is to close all plot windows, fork, and re-open them.
That's what's causing the GUI plot window to detach: I haven't coded the bit that would re-open it at the correct window id (the drawing area inside the GUI).
Will fix in next release, or send you a patch when I get around to fix the code.
Francois