All of a sudden I have a set of yellow dashes forming a horizontal line and a vertical line on my chart (candlestick price chart). The horizontal line is [apparently] fixed on the x-axis (date axis), and the vertical one is [apparently] fixed on the current date. I've never seen them before, I don't know where they came from, and, more importantly...I don't know HOW TO GET RID OF THEM? Any help appreciated.

IBJAMIN,

This is probably a plot on your chart. You mentioned that the dashes are yellow. Look at the indicators on your chart and find the indicator that is labeled in yellow. Click the yellow indicator and select Edit. You may have the line style to dashes instead of a regular line. If you don't want the line/ dashes there at all just click the indicator and select Delete. 

The vertical line is a drawing tool. You should be able to highlight the vertical line with your mouse and click on it. You will have the option to delete it.