JBDS-3007 - JBoss Central tooltip
JBIDE-17507: Improvement on error message in Central
JBIDE-17514 JBIDE-17425: Better handling of scroll

This fixes issue of scrollbar not being updated when
content of the scrolled composite is resized.
JBIDE-17474: Bigger size for install/uninstall buttons
JBIDE-17531 : check for disposed widget

Signed-off-by: Fred Bricon <fbricon@gmail.com>
JBIDE-17529 : disable (un)install buttons during refresh

Signed-off-by: Fred Bricon <fbricon@gmail.com>