User Story

As an application dev, I want to specify a CSS relative unit e.g. %, em on those LayoutRegion (north, south, west, east) so that I can keep responsive to any device size.

Acceptance Criteria

provide API to accept CSS relative units.

Details

• The current design: setMaxSize() only accept an integer as the number of pixel.
• Although you can specify CSS max-width: 15% to limit the size in a relative unit but maxsize can stop end-users from dragging over the max size:
  

If you use CSS syntax, there is no such UI dragging effect.