add class desc
remove unused Tab key handler
add getPath util method
move @optional
add todo to replace other selections
add hasSelection
set selection instead of set focus
31: remove selection in non visible tabs 
Task-Url: http://github.com/webcane/EclipseCommander/issues/issue/31
remove todo
31: remove selection in non visible tabs 
Task-Url: http://github.com/webcane/EclipseCommander/issues/issue/31
remove other selections when part was activated