Horizontal lines are just lines, they don't have such label that comes with them. These labels are different kind of objects. It's not impossible to create labels and move them with the lines, but this does not exist in fxDreema... at least not in one block.
How this can be done... at least on theory - It is possible to catch the event of moving any object (event like this would happen very often, multiple times per second depending on the speed of moving your mouse). In that event I imagine that the name of the horizontal line can be read and with that name the label with similar name could be found. Then the idea is to move the label at certain distance from the line.
And I'm only speculating on this, because I'm not even sure that you can do something like this at all. Now that I'm thinking more, I know 2 types of text objects that can be printed on the chart:
One of them can be positioned absolutely - at certain pixels from the top and the left. In MetaTrader this is the T icon. But this object does not move with the chart! While the horizontal line does.
The other can be positioned vertically on certain price and horizontally on certain time (candle). Basically the same way that any arrow is positioned. But what is the time (candle) at the right side of the screen where normally you don't even see candles?