(I ran out of room to complete the issue, thanks for more space.) Originally the Firefox icon was on the dock, then disappeared. I noticed on the screen the orange hard drive picture with the Firefox on the icon, tried to move it from the screen to the dock, it would not stay. It kept bouncing back to the main screen. So I clicked on the orange icon and a box opened with the regular (circular) Firefox icon, and an arrow to the right with an "A" for applications on a folder. When I did what it indicated (moved the icon to the folder) a question came on screen; You already have the Firefox, do you want to install this older version? I clicked on "Cancel". Then I went to "Find", then clicked on, "My Computer" and opened it, found the Firefox icon and clicked and drug the icon to my dock. The icon stayed on the dock. Then I thought, I'll check to see what version I have. The message said it is time for an update for Firefox, do you want to now? I clicked, yes. It updated to version 20.0 and said, "You are currently on the release update channel". What does all this mean? Why did the icon vanish from the dock originally? I have a Mac OSX, 10.7.5