Right after finishing the installation process, PopUp Killer will appear in your tray area as yellow lightning icon (), (see figure 1)

PopUp Killer uses the icon in the tray area to show its current state, depending on various conditions: Not connected to the Internet When you are offline, PUK will enter in a sleep mode, which consumes less resources and CPU time.

Figure 1

Connected to the Internet
When you connect to the Internet, PUK will automatically detect your connection and enter the active state.

Not connected, but Working Offline
You can force PUK to enter the active state by enabling the Work Offline option from the Preferences menu. This is useful if you browse web pages offline (locally), or use either an unsupported dialer or Windows language. (See the Known problems and limitations section for further information.)

Disabled
You can temporarily disable PUK from detecting PopUps. This may be useful if by some (weird) reason you want to see the PopUps in the web pages you're visiting. Use the Disable option from the Preferences pulldown menu to enable this state.