Locked?

[Dimsok]

What the meaning of "locked" protocols? When click on the uppest icon of every protocols... What the job that do?

[Vulpix]

I am not sure if there is anything else to it other than that these protocols do not follow "global miranda status", i.e. when you right-click your miranda tray icon and select status->online (for example), locked protocols will not follow the new status.

[AnrDaemon]

"Locked" protocols won't be affected by global status changes and will remain in whatever state you have them locked. (I.e. if you smash Ctrl+0, when you have ICQ locked in Online status, all protocols will go offline, except ICQ.)
Only if you directly change said protocol status, it'll be changed, but will remain locked (now to a new status).