Having activated the CCleaner option to minimize to tray... clicking over the icon (pinned in taskbar) of CCleaner will open one CCleaner... clicking again will minimize to try that one and clicking again will open another session/window no matter if there is one already opened even stopped or running!
btw MrT I feel kinda annoying having to double click taskbar icon to restore CCleaner from Tray... it doesn't feel well in the hidden icons in Windows 7 cause many times you double click and then open CCleaner and the next software besides it..