Bug 59037 [Navigator] Package explorer flicker when switching/closing editors
If 'Link with editor' is active I see a lot of redrawing going on in the Package Explorer view when I switch between editors (or close an open editor). If the file opened in the second editor already appears in the Package Explorer, it is simply selected and there is no flicker. If, however, the view has to be scrolled to show the second file, I see a lot of redrawing before the view is shown in the new position. The Outline view also seems to draw a white background before drawing the content for the active editor, but it's not nearly as annoying as the Package Explorer (it's true that hte PAckage Explorer has much more items, though).
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
Item[] children = getItems(item);
        if (getExpanded(item) && children != null && children.length > 0) {
            return rightMostVisibleDescendent(children[children.length - 1]);
        }
        return item;
    }
    
    public Item scrollDown(int x, int y) {
        Item current = getItem(x, y);
        if (current != null) {
            Item next = getNextItem(current, true);
            showItem(next == null ? current : next);
            return next;
        }
        return null;
    }
    
    public Item scrollUp(int x, int y) {
        Item current = getItem(x, y);
        if (current != null) {
            Item previous = getPreviousItem(current);
            showItem(previous == null ? current : previous);
            return previous;
        }
        return null;
    }
    /**
     * Sets the auto-expand level. The value 0 means that there is no
     * auto-expand; 1 means that top-level elements are expanded, but not their
     * children; 2 means that top-level elements are expanded, and their