Once a test has produced zones, a bar appears under the canvas. Dragging it moves the canvas through the run, and the zone blocks change state as you go.
The four states
Not there yet — the zone does not exist at this bar. Formed, not readable yet — it exists on the chart but the strategy is not allowed to use it. Readable — it may be used from here. Gone — price invalidated it.
The gap between the second and third state is the part worth watching. It is the non-repainting guarantee made visible: a zone is drawn at one bar and only becomes usable at a later one, and nothing in the test reads it before the bar that confirms it.
Why this matters
Most backtests that look too good are reading something they could not have known at the time. A zone that becomes tradeable the moment it appears on a chart is exactly that mistake, and it is invisible in a table of results.
The strip on each zone node shows the whole life — formed in amber, readable in the zone's own colour, with a playhead at the bar you are looking at.
Runs without zones
No bar appears. A strategy with no zone blocks has nothing that changes as the test moves, and a control that does nothing is worse than no control.