GUI2 Added selection of background maps

Change-Id: I88ee69fe2ff24bb1b4b3fe633b04f2f1778f3a82
diff --git a/web/gui2/src/main/webapp/app/view/topology/panel/toolbar/toolbar.component.ts b/web/gui2/src/main/webapp/app/view/topology/panel/toolbar/toolbar.component.ts
index f781364..ed9e2ee 100644
--- a/web/gui2/src/main/webapp/app/view/topology/panel/toolbar/toolbar.component.ts
+++ b/web/gui2/src/main/webapp/app/view/topology/panel/toolbar/toolbar.component.ts
@@ -30,6 +30,7 @@
 export const OFFLINE_TOGGLE = 'offline-tog';
 export const PORTS_TOGGLE = 'ports-tog';
 export const BKGRND_TOGGLE = 'bkgrnd-tog';
+export const BKGRND_SELECT = 'bkgrnd-sel';
 export const CYCLELABELS_BTN = 'cycleLabels-btn';
 export const CYCLEHOSTLABEL_BTN = 'cycleHostLabel-btn';
 export const RESETZOOM_BTN = 'resetZoom-btn';