When you change settings in the KDE control panel, when you press 'Apply' besides saving the new configurations in the respective config file, what other functions are performed.

I made a script that edits the proxy settings in the KDE control panel, but the problem is these new settings don't come into action, but obviously if i open the control panel, the settings are changed as desired. But they would not be in action, hence i am assuming the apply button does more than save the settings in the config file.

I think I can explain the concept, if not the specifics. I'll use an example from the bash shell to illustrate.

Suppose you make changes to ~/.bashrc, a new prompt, or command alias. The changes are in the file when you save it, but the changes don't go into effect until one of four things happens:
a) log out, then log in
b) restart the X windows server
c) reboot (unnecessary, but is one way of doing it)
d) run the command 'source ~/.bashrc' (or '. ~/.bashrc')

Sourcing .bashrc reloads the bash environment, which contains the changes you have made.

Something similar is happening in Kde. You change the preferences via script, but they don't go into effect until you reload the environment. In Kde, pressing the 'Apply' button has the same effect as d) above, and reloads the Kde environment so that the changes go into effect.

yeah, i figured so far, but thanks for explaining it constructively, how can I found out what kde is doing when you press 'apply' ?