Hey, I did a quick search, and couldn't find a topic about this...

Anyways, I think that Sketchbook should run the client program in another thread.
Because, what if I do something stupid and the program ends up in an infinite loop? Or if it takes a lot of time to do something?
I end up with terminating the process, which also terminates the editor - this means, that I lose changes!
And if I'm not careful, and forget to save (I tend to save very often, saying for other people now), I could lost hours of work!

Well, that's what I meant - to put the COMPLETE program in another thread - right now, it doesn't look that way.

And if you think about it, it might have been done this way, without threads (pseudo-code):
--------------------
gui_update();
program_setup();
while(window_open(processing))
{
 gui_update();
 if(window_open(program))
 {
   program_callbacks();
   program_draw();
 }
}
--------------------

Basically, it runs the drawing in the same thread, the only difference is that it also does GUI update in the loop...
That would explain the fact that while(true) loops in the program (program = sketch) stop the whole IDE from working... Processing stops at while(true) inside program_draw()

Well, another explanation would be this (same effect):
--------------------
Thread main;
Thread prog;

main.gui_update();
prog.program_setup();
prog.wait(); // waits for the thread to return
while(window_open(processing))
{
 main.gui_update();
 if(window_open(program))
 {
   prog.program_callbacks();
   prog.wait();
   prog.program_draw();
   prog.wait();
 }
}
--------------------
PS: Yes, I know that this isn't how the actual program works (I really don't feel like looking into its code either), hence the term pseudo-code.