fix javadoc error
minor fix
Merge branch '7.0' of github.com:zkoss/zk into 7.0
fix IE scrollbar vibrating issue
fix img ver-align style
the width of window should not shrink when the window max
the width of header should change when the border between 
the two headers is dragged
the bg of listitem shouldn't be covered when the bg of listbox is given
fix for ie10
the size should not change when the browser resize
click the left icon should scroll now
fine tune errorbox