FVGs & CEs + Alerts: simple & efficient method

Fair Value Gap indicator: Paints FVGs and their midlines (CEs). Stops painting when CE is hit, or when fully filled; user choice of threshold. This threshold is also used in the Alert conditions.
~~Plotted here on ES1! (CME), on the 15m timeframe~~

-A FVG represents a 'naked' body where the wicks/tails on either side do not meet. This can be seen as a type of 'gap', which price will have a tendency to want to re-fill (in part or in full).
-The midline (CE, or 'Consequent encroachment') of FVGs also tend to show price sensitivity.
-This indicator paints all FVGs until priced into, and should give an idea of which are more meaningful and which are best ignored (based on context: location, Time of day, market structure, etc).
-This is a simpler and more efficient method of painting Fair value gaps which auto-stop painting when price reaches them.

//Aims of Publishing:
-Education of ICT concepts of Fair Value Gaps and their midlines (CEs): To easily see via forward testing or backtesting, the sensitivity that price shows to these areas & levels.
-Demonstration of a much more efficient way of plotting FVGs which terminate at price, thanks to a modification of @Bjorgums's clever looping method referenced below.

//Settings:
-Toggle on/off upward and downward FVGs independently(blue and orange by default).
-Toggle on/off midline (CE).
-Standard color/line formatting options.
-Choose Threshold: CE of FVG or Full Fill of FVG: This will determine both the 'stop-painting' trigger and the 'Alert' trigger.
-Choose number of days lookback to control how many historical FVGs paint on chart.

//On alerts:
-Simple choice of 2 alerts:
~~One for price crossing into/above the nearest untouched 'premium' FVG above ( orange ). Trigger is user choice of CE or full fill.
~~Another for price crossing into/below the nearest untouched 'discount' FVG below (blue). Trigger is user choice of CE or full fill.
-Alerts set via the three dots in indicator status line.

//Cautionary notes:
-Do not use the alerts blindly to find trades. Wait until you have identified a good FVG above/below which you think price may show sensitivity to
-Usage on very low timeframes can cause unexpected results with alerts: due to new FVGs forming in realtime the Alert will always trigger at the most recent FVG above/ below having its threshold hit.

-Big thank you to @Bjorgum for his fantastic extendAndRemove method. Modified here for use with boxes and to integrate Alerts.
-Also Credit to ICT (inner circle trader) for the concepts used here: Fair value gaps and their Consequent Encroachment (CE).

Release Notes:

-Toggle box to delete filled FVGs & CE lines entirely once filled or threshold crossed (default is OFF)

Release Notes:

-Added IOFED alerts (insitutional order flow entry drill: ICT concept): Optional alert for when price merely enters FVG (crossing above the low of FVG above, or crossing below the high of FVG below).
--These alerts are unaffected by the indicator dialog box toggle box (unlike the above/below threshold alerts: CE or Full Fill)

Release Notes:

-Added two more alerts for the simple confirmation of newly formed FVGs (bottom two alerts from the list of six)
-Clarified Alert titles & messages

Release Notes:

~Added two more simple alerts for UN-Confirmed FVGs. See the dropdown list of alerts. Un-confirmed means you get early alert as soon as FVG forms, NOT waiting for the realtime bar to close and confirm the FVG.