some programs do not show up in OD2 taskbar for me i.e. x-plane simulator or Left4Dead2 (steam version).
Not as windows (minimized or not) and not as applications when show running applications is selected.
Everytime i play L4D2 or the flightsim i have to show the windows taskbar only for that reason.
Windows7-64 / AMD PH2 940 / EN8800GTX here.