perl/tk . deactivate windows

Hi ..
I wrote a windows application in perl/tk.
I would like to deactivate parent windows when I open new one.
for example :

lets say I am in the main window now and I press on the "configuration" button.
after I press the configuration button , a new window started ,.
I would like to deactivate the main window (so I cannot even press it) and reactivate it when I shut down the configuration window.

is there any method to deactivate window in perl tk ??

Thanks a lot in advanced.

Ido Ofzer