title: ExtJS: east/west region to occupy available space when other regions are not present
body: <p>Iam using border layout for my application.I want to make east/west region to occupy the available space whenever other regions are hidden or not present.
  For example if east and center regions are there, if center region is made hidden, automatically east region should occupy the space available.
  Please suggest your ideas to achieve this.
  Thank You.</p>