i start a script that starts a big application. this application often takes several seconds before it opens its window. what i would like to do in the script is open a splash window, quickly, so that i know it is starting and that i do not need to click on its icon, again. sometimes, when i click on things, it just doesn't really do anything and i need to click it, again. if i start two instances of this application, is causes problems and i need to shut both of them down, start it again, and in the 3rd instance, clean up the mess. so i really want a good way to know that my click worked or not.

What sort of script? Which language?

I'm sure most languages would allow you to paint an image on the desktop until your application is ready, I really don't see a problem there.

Also look into startup-notify.

a script as described. what detail do you need about the description? what did my description fail to tell you?

the existing script is in Python. it can invoke a splash program in any form. but, for safety, i want source. if needed, i'll compile/make it. but, Python would be preferred since i may be able to mod my script to do the splash directly. i have never done any GUI coding in any language.

A search for "GTK Hello World" turns up four sample programs on the first page. You can add a timer to automatically close the window.
Ed