Bug 72297 [DnD] ViewerDropAdapter impossible to set DND.FEEDBACK_NONE
It is not possible to disable selection feedback in ViewerDropAdapter. There are setFeedbackEnabled(false) and setScrollExpandEnabled(false) methods to turn off the feedback effects. If those methods are used, selection feedback still provided. It is not possible to turn it off, elements are still selected when drag is over them. Overriding method; private void setFeedback(DropTargetEvent event, int location) { event.feedback = DND.FEEDBACK_NONE; } - does not chenge the feedback either. setFeedbackEnabled() should be extended to disable SELECTION feedback or new method created, setSelectionFeedback().
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ViewerDropAdapter.java
return LOCATION_BEFORE;
            }
            if ((bounds.y + bounds.height - coordinates.y) < 5) {
                return LOCATION_AFTER;
            }
        }
        return LOCATION_ON;
    }
    /**
     * Returns the target item of the given drop event.
     *
     * @param event the event
     * @return The target of the drop, may be <code>null</code>.
     */
    protected Object determineTarget(DropTargetEvent event) {
        return event.item == null ? null : event.item.getData();
    }
    /* (non-Javadoc)
     * Method declared on DropTargetAdapter.
     * The mouse has moved over the drop target.  If the
     * target item has changed, notify the action and check
     * that it is still enabled.
     */
    private void doDropValidation(DropTargetEvent event) {
        
        if (event.detail != DND.DROP_NONE) {
            lastValidOperation = event.detail;
        }
        
        if (validateDrop(currentTarget, event.detail, event.currentDataType)) {