how to extend horizontal line on column graph

[bos1234]

Hi
I have the chart below. I am trying to extend the horizontal line so that it spans the whole of the x-axis
How can this be done? I have attached the excel file.

I have tried selecting "on tick marks" but that cuts the left hand and right hand portion of the graphs


View image: a

 

[Worf]

Hi
How was the line generated? Is it a clickable object?

I have attached the excel file.

You have not, this forum doesn´t allow attachments. However, it would be a good idea if you could post the file at a hosting site so that we could work on the real chart.