Notice the message below have 3 line items with content, plus the Background line item for a total of 4 line items.  The line that is labeled electric is 1 second long, the line labeled time is 2 seconds long and the line labeled temp is 2 seconds long for a total time of 5 seconds long.

Lets say this customer would like the message to be only 4 seconds long. We will then remove 0.5 seconds from the time and 0.5 seconds from the temp simply by clicking on the right end of the  time and shrinking it down to 1.5 seconds, then clicking on the right end of the temp and shrinking it down to 1.5 seconds.  Then we will need to move the temp over to the left so it will line up under the end point of the time.

But we are not done, the message is still 5 seconds long!! Notice in the picture above the line item that is labeled Background is still 5 seconds long, it will have 1 second of blank/black.  You need to click on the right end of the background line and shrink it down to 4 seconds (you can only shrink it down to match the line items).