DeckPanel now calls setVisible(true) on the Widget that is currently being displayed so users can implement delayed rendering techniques in their widgets.  This supports a legacy use case where users relied on setVisible being called.

Patch by: jlabanca
Review by: ecc (desk review, branch-info.txt not reviewed)
Issue: 2510



git-svn-id: https://google-web-toolkit.googlecode.com/svn/releases/1.5@3056 8db76d5a-ed1c-0410-87a9-c151d255dfc7