ONOS-1865 - GUI -- Keys from Topo View are deregistered once view is navigated away from. Device and App View 'esc' key registration added.

Change-Id: I88896266936a4f148007170d67058036fb365fe5
diff --git a/web/gui/src/main/webapp/app/view/device/device.css b/web/gui/src/main/webapp/app/view/device/device.css
index e4a30b1..fc08f68 100644
--- a/web/gui/src/main/webapp/app/view/device/device.css
+++ b/web/gui/src/main/webapp/app/view/device/device.css
@@ -31,6 +31,7 @@
 #device-details-panel.floatpanel {
     -moz-border-radius: 0;
     border-radius: 0;
+    z-index: 0;
 }
 
 .light #device-details-panel.floatpanel {