Hello, I am doing a small protection system for MOS, to protect the system better my screen should be always in front.
Does anybody know a way to achieve this?

Another problem I encoutered, is that my tool which resides in wbstartup is not started at least how can I do that so the screen opened by my tool is always in front after the start?

Can't you determine when opening a screen, if you want it to front or not?

I don't have my C sources nearby, so I can give you better answer...

If you wanted to create sort of "login screen" one more choice would be fullscreen window (on Ambient screen), that has no depth gadget and is frontmost...

Well, have you ever clicked a window which
hides the upper right corner ? ;)

You click right through it and switch screen.

(Not tested)

Open a backdrop-window as Jupp suggested.
Wait for IDCMP_INACTIVEWINDOW.
Reactivate Window and bring Screen back to front when you receive it.
May result in minor flicker.

@Robin
Hiding the bottom is of no use as one might know the KBD-shortcut, or
apps on the Ambient-Screen may bring it back to the top (for example when
mail arrives).

Apps in WB-Startup do need an icon (AFAIR), and that should be
Type : Tool and the Executable checkbox should be selected.
Also include DONOTWAIT in the tooltypes.