4D automatically manages process priorities. The frontmost process has priority over others only when it is being used for data entry. Between two spaced keystrokes, 4D gives processing time to other processes. The only way to force absolute priority to a process is by freezing all others. Therefore if you have a process which must execute as quickly as possible for the user you can pause all other processes over which you have control and hide them. This gives the most priority to the user's process.