Key TakeawaysDollar Tree shares rose ahead of Tuesday’s opening bell after the discount retailer reiterated its fiscsl third-quarter outlook and said its CEO was stepping down.Since reaching their early-September low, Dollar Tree shares have formed two distinct troughs around the same level on the chart, raising the possibility of a double bottom, a classic pattern that signals a potential upside trend reversal.Investors should monitor key resistance levels on Dollar Tree's chart around $77, $92, and $104, ...