Use some Indicator for define Demand and Supply Zone such as Below Moving Average 200 -150 Supply Zone and Above Moving Average 50 - 100 for Demand Zone
Create the variable.
Do not use delete objects. That causes all of them to be deleted when price break any mark. You only want the ones deleted that price has broken so use the delete bloc under the loop for chart object section.
I don't think it's a bug or anything. Sometimes you have to tinker around with things to get it to work.
It is possible but difficult, you would need to get the value using a formula, then draw a trend line on the relevant value and place, and then write the relevant text.
Here it is better to use candle "1" because candle "0" is also the market price, although not the middle one but it could be due to such a constellation.
@DragonZueloTrends solution is how to get it working on mouse click, my issue with doing it this way first is it only works on live/demo charts. I set it up on tick, under a testing block, and then when working I copy it onto on chart, this way I can test it all at speed.