private void setResizeEnabled(final boolean enabled) {
        resizeN.setVisible(enabled);
        resizeE.setVisible(enabled);
        resizeS.setVisible(enabled);
        resizeW.setVisible(enabled);
        resizeNE.setVisible(enabled);
        resizeNW.setVisible(enabled);
        resizeSE.setVisible(enabled);
        resizeSW.setVisible(enabled);
    }
Called on mouse up in the caption area, ends dragging by ending event
capture.

@param event the mouse up event that ended dragging
@see DOM#releaseCapture
@see #beginDragging
@see #endDragging
stroom-core-client-widget/src/main/java/stroom/widget/popup/client/view/ResizableDialog.java