Bug 205923 [Viewers] Javadoc for setAllChecked() does not mention that only visible items are checked
setAllChecked which was added (by me) in 3.2 does not mention that all chidren must be visible for it to be checked (see setSubtreeChecked). We will have to leave it as it is API and does not expand the tree but I think we should deprecate it as setSubtreeChecked is really the only useful one. Boris what is your opinion?
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/CheckboxTreeViewer.java
return ((TreeItem) widget).getChecked();
		}
        return false;
    }
    /**
     * Returns a list of checked elements in this viewer's tree, 
     * including currently hidden ones that are marked as
     * checked but are under a collapsed ancestor.
     * <p>
     * This method is typically used when preserving the interesting
     * state of a viewer; <code>setCheckedElements</code> is used during the restore.
     * </p>
     *
     * @return the array of checked elements
     *
     * @see #setCheckedElements
     */
    public Object[] getCheckedElements() {
        ArrayList v = new ArrayList();
        Control tree = getControl();
        internalCollectChecked(v, tree);
        return v.toArray();
    }
    /**
     * Returns the grayed state of the given element.
     *
     * @param element the element
     * @return <code>true</code> if the element is grayed,
     *   and <code>false</code> if not grayed
     */