Unfortunately, if this arrow appeared without delay at all, then it could be redrawn, i.e. give false signals.   Here is an uncertainty relation that is not overcome by any filtering: Either a reliable signal with a delay, or a signal without a delay, but with low reliability.

This indicator has all kinds of alerts.

Thank you very much for the screenshot and fast response!

Thank you very much for your fast response!

This is a very sensitive indicator (it reveals latent information that does not allow identifying less sensitive indicators). And, in the case you noticed, it shows how your broker or dealing center deceives you by playing against you. When the indicator hangs on the chart for a long time and you watch the latest events on the chart, the data comes in real time, i.e. you see what the broker gives you directly and what you play on. In particular, the spread widens. When you update the chart, you take information from the history, into the database of which the broker loads slightly different data (in particular, with a smaller spread, and this is a well-known effect). This can give a change in the indicator readings.

MQL4 does not provide the ability to change the font size of messages on charts. When I have time, I will make a separate panel for this.   The color of the red trend line, if it bothers you, change the color in the settings to None (at the top of the color gamut).