How to keep a text box visible on the chart

Text disappears from some of my charts as soon as I hit enter, but is ok on others.

If you plotted any of your indicators with the ‘overlay without scale’ option selected and typed your text near that indicator, your text will not be attached to a scale and will not be seen on your chart. When you type your text in a chart, it takes the nearest objects scaling. So make sure that where you start typing is near an object that has a fixed scale, such as the prices. You can then drag the text box to the desired location.  Otherwise, type your text away from any indicator/trend lines or price bar.