Bug 232777 [Viewers] ViewerDropAdapter holds currentTarget forever
Build ID: 3.3.2 Member currentTarget should be set to null after drop or after cancel, because it holds a domain object, which can't be garbage collected after Viewer.setInput(null).
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ViewerDropAdapter.java
* Sets whether selection feedback should be provided during dragging.
     *
     * @param value <code>true</code> if selection feedback is desired, and
     *   <code>false</code> if not
     *   
     * @since 3.2
     */
    public void setSelectionFeedbackEnabled(boolean value) {
        selectFeedbackEnabled = value;
    }
    /**
     * Sets whether auto scrolling and expanding should be provided during dragging.
     *
     * @param value <code>true</code> if scrolling and expanding is desired, and
     *   <code>false</code> if not
     * @since 2.0
     */
    public void setScrollExpandEnabled(boolean value) {
    	expandEnabled = value;
    	scrollEnabled = value;
    }
    /**
     * Sets whether auto expanding should be provided during dragging.
     *
     * @param value <code>true</code> if expanding is desired, and
     *   <code>false</code> if not
     * @since 3.4
     */
    public void setExpandEnabled(boolean value) {
        expandEnabled = value;