title: Cursor related issue for Qcustom Plot
body: <p>I want to add a two vertical cursor on x-axis only, the first cursor is on the start position like on 0 and the second cursor is on end position(i.e. any limit like 250 or 300 like wise).</p>
  <p>But when i move mouse on the plot the plot getting black i don't know how can any one help me for this please.</p>
  <p>Thanks in advance.</p>