The London Breakout strategy (according to my personal understanding) basically sees the morning before London open as the accumulation or distribution range for large buyers or sellers, and assumes the market will break either above that mornings high or below that mornings low when they start to move price. It is mostly used to trade stock indices and forex.
This indicator plots the morning high and low for each day. The green line is the morning high, and the red line is the morning low. If price moves above the green line (the morning high) it fills that area with a green color. If price moves below the green line (the morning low) it fills that area with a red color. This makes the breakouts easy to spot.
The background color of the chart turns green when the MDX is above 0 (price is more than X times ATR above the mean) and a breakout above the morning high has occurred, and stays green until the opposite happens.
The background color of the chart turns red when the MDX is below 0 (price is more than X times ATR below the mean) and a breakout above the morning high has occurred, and stays green until the opposite happens.
The default for X above is 1.0, but this can be changed in the settings by changing "ATR Multiplier".
The background is always neutral during the morning session since the morning high and morning low are not established yet.
A trailing stop is shown when price is more than X times away from the mean and a breakout has occured. The distance is set using the MDX. The trailing stop uses a separate ATR multiplier though, to make the signal and trailing stop MDX values different, if one likes. The default ATR multiplier for the trailing stop is 1.25, but this can be changed is the settings by changing "ATR multiplier for trailing stop".
When the high or low of a candle breaks the trailing stop, it is moved further away, indicating you have been stopped out, but gives opportunity to use it if you enter again (so it doesn't just disappear).
As an added bonus, take profit levels have been added based on the mornnig range. The take profit distance is set by multiplying the range with a factor. The levels are then plotted that distance from the morning high and morning low.