Fixed issue of error message not getting displayed when filename is empty for backup, restore, and import/export. Fixes #3814.

web/pgadmin/static/scss/_alert.scss

@@ -87,6 +87,12 @@
     }
   }
 }
+.alertify_tools_dialog_properties .pg-prop-status-bar {
+  position: absolute;
+  right: 0;
+  left: 0;
+  bottom: 0;
+}
 
 .pg-prop-status-bar {
   padding: 5px;