Why doesn't my CSS pop-up message span the width of the browser viewport in IE?

Question

I have this for my popup message (like stackoverflow has, you know the "You have earned a badge" "You have new responses" at the top):

#message {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 105;
    background-color:blue;
    font-family:Arial,Helvetica,sans-serif;
    font-size:100%;
    text-align:center;
    font-weight:bold;
  height: 26px;
  width: 100%;
}

Now, I am not good with CSS, but I would like to have an fix for IE. With Firefox, the message box spans the viewport from left to right:

+------------------------------------+
|<---------------------------------->|
|                                    |

...but with IE it reaches the left edge of the viewport, but then it stops like 2 cm before the right edge:

+------------------------------------+
|<---------------------------------> |
|                                    |

Any idea why?

Answer 1

try setting right:0 aswell as left:0. You can simultaneously set left and right when positioning absolute.