Usage patterns
〈事〉が広がりを見せるfor something to show signs of spreading
The news is showing signs of spreading both domestically and abroad.
〈物〉に広がりがあるfor something to have breadth or depth
This painting has a real breadth of color.
〈事〉に広がりを持たせるto give something more scope or range
To give the discussion more breadth, other viewpoints were also introduced.