When any of the docked tab(statistics, dependents & dependencies)

are clicked without selecting any tree node. it gives error in browser
console panel.
Because the node passed is undefined. and check is missing. This is now
fixed by adding check for node passed.

web/pgadmin/misc/depends/static/js/depends.js

@@ -236,6 +236,9 @@ define(
        * through. We will wait for some time before fetching the Dependents
        **/
       var self = this;
+      if (!node) {
+        return;
+      }
       self.dependent = true;
       if (self.timeout) {
         clearTimeout(self.timeout);
@@ -275,6 +278,9 @@ define(
        * through. We will wait for some time before fetching the Dependencies
        **/
       var self = this;
+      if (!node) {
+        return;
+      }
       self.dependent = false;
       if (self.timeout) {
         clearTimeout(self.timeout);