obmint.uc.js

// ==UserScript==
// @name    (always) Open Bookmarks in New Tabs
// @compat  Firefox 20+
// @author  satyr
// @license X
// @include main
// ==/UserScript==
PlacesUIUtils.openNodeWithEvent =
function PUIU_openNodeWithEventInNewTab(node, event, view) {
  var where =
    PlacesUtils.nodeIsBookmark(node) &&
    PlacesUtils.annotations
      .itemHasAnnotation(node.itemId, this.LOAD_IN_SIDEBAR_ANNO)
    || node.uri.startsWith('javascript:')
    ? 'current'
    : event.button
      ? 'tabshifted'
      : 'tab'
  this._openNodeIn(node, where, view.ownerWindow)
}