Family Dollar has long been an anchor dragging at Dollar Tree. That's over now.

A Family Dollar store in Fairfield, California.

Justin Sullivan/Getty Images

• Dollar Tree says it has reached a deal to sell its long-struggling Family Dollar chain.
• The $1 billion sale comes a decade after the company bought the former rival.
• For most of that time, Dollar Tree was unable to find a way to make the brand perform well.

It's a new day for Dollar Tree.

The discount chain said Wednesday that it has reached a deal to sell its long-struggling...