Could be that something in het new firefox version is causing this issue.
If you open application in firefox and press F12 (firebug) and click the console option. After that open the dataview containing the microflow button and see if the console mentions any errors.
Other option is to change index.html to index-console.html in the url. This way more output comes to the console.
Yes, I do get an error message: "too much recursion" in "http://localhost:8080/mxclientsystem/dojo/dojo.js" line number 14
columnNumber: 27728
the stack is: "dojo.Deferred/this.errback@http://localhost:8080/mxclientsystem/dojo/dojo.js:14:27729102@ http://localhost:8080/mxclientsystem/dojo/dojo.js:14:27471100@http://localhost:8080/...