I set up a dashboard which was running for a few minutes, then I manualy edited the widget data file to set the "enableSpinner" to true (no doco so I was testing it).. deleted 2 widgets and moved a third, after which the name of every widget changed to the dashboard name and the AJAX calls suddenly started firing continuously.
To replicate I deleted a status_table first , then an alert widget then moved a meter widget, its very repeatable!
[{"id":38323,"name":"Memory","kind":"meter","size":null,"source":"demo","targets":null,"range":"30-minutes","dashboard_id":222,"created_at":"2014-02-17T23:55:23.778Z","updated_at":"2014-02-17T23:55:23.778Z","update_interval":10,"col":3,"row":4,"size_x":1,"size_y":2,"min":0,"max":100,"aggregate_function":"average","label":"Free Memory","enableSpinner":true},
{"id":38333,"name":"HTTP","kind":"number","size":null,"source":"demo","targets":null,"range":"30-minutes","dashboard_id":222,"created_at":"2014-02-17T23:55:54.401Z","updated_at":"2014-02-17T23:55:54.401Z","update_interval":10,"col":3,"row":1,"size_x":1,"size_y":1,"use_metric_suffix":true,"graph_type":"area","aggregate_function":"average","label":"Requests","enableSpinner":false},
{"id":38353,"name":"Stats Gathering","kind":"ci","size":null,"source":"demo","targets":null,"range":null,"dashboard_id":222,"created_at":"2014-02-17T23:57:40.659Z","updated_at":"2014-02-17T23:57:40.659Z","update_interval":10,"col":3,"row":3,"size_x":1,"size_y":1,"enableSpinner":false},
{"id":38363,"name":"Status-Table","kind":"status_table","size":null,"source":"demo","targets":null,"range":null,"dashboard_id":222,"created_at":"2014-02-17T23:58:32.581Z","updated_at":"2014-02-17T23:58:32.581Z","update_interval":60,"col":4,"row":1,"size_x":1,"size_y":3,"enableSpinner":false},
{"id":38373,"name":"Alert!","kind":"alert","size":null,"source":"demo","targets":null,"range":null,"dashboard_id":222,"created_at":"2014-02-17T23:58:52.579Z","updated_at":"2014-02-17T23:58:52.579Z","update_interval":10,"col":1,"row":5,"size_x":2,"size_y":1,"enableSpinner":false},
{"id":38383,"name":"System Health","kind":"boolean","size":null,"source":"demo","targets":null,"range":null,"dashboard_id":222,"created_at":"2014-02-17T23:59:12.453Z","updated_at":"2014-02-17T23:59:12.453Z","update_interval":10,"col":3,"row":2,"size_x":1,"size_y":1,"label":"Bool-1","enableSpinner":false},
{"id":38393,"name":"Process Activity","kind":"graph","size":null,"source":"demo","targets":"target","range":"30-minutes","dashboard_id":222,"created_at":"2014-02-18T00:00:22.855Z","updated_at":"2014-02-18T00:00:22.855Z","update_interval":10,"col":1,"row":1,"size_x":2,"size_y":2,"graph_type":"line","max":100,"enableSpinner":false},
{"id":38403,"name":"Area Graph","kind":"graph","size":null,"source":"demo","targets":"Target A","range":"30-minutes","dashboard_id":222,"created_at":"2014-02-18T00:01:52.962Z","updated_at":"2014-02-18T00:01:52.962Z","update_interval":10,"col":1,"row":3,"size_x":2,"size_y":2,"graph_type":"area","max":250,"enableSpinner":false}]