Repainting indicators and the screenshots that sell them

[Amanhasnoname]

Some indicators change their past signals when new data arrives. An arrow that appeared at a perfect turning point was actually placed afterward, once the turn was obvious.

Screenshots of such indicators look flawless, which is why they are popular in marketing. Live, the arrows appear late, move, or vanish, and the strategy built around them fails.

A simple test: watch the indicator live for an hour with the screen recorded, then compare the recording to the final chart. If signals are different, it repaints.

Some repainting is natural, such as a developing bar. The issue is when completed bars change. Zigzag, fractal-based tools, and some trend line indicators are the usual culprits.

A scalper relying on such tools makes decisions on a moving target. The backtest results mean nothing, since they use the final, corrected signals.

The safest approach is preferring indicators that only compute on closed bars, or ones that are clearly documented as non-repainting and verified.

Has a repainting indicator ever fooled you, and how did you discover it?