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The first step to solving this issue is to understand which control(s) are causing this issue. The Firebug tool, http://getfirebug.com in the Firefox browser is a great way to find hidden controls which are invalid or required and causing the submit button to remain disabledempty. Test your form and enable the firebug tool. Open firebug's HTML tab and search for all instances of s-invalid using the search box in the tool's top-right corner. This will take you to the HTML of each control in the invalid state. The control's name can be found in that HTML. Now you can edit your form in the designer, find that control and fix the issue.

Note that if a required control is inside a hidden section, then that section will also be invalid and you will also see s-invalid in the section control's HTML. This s-invalid is not the root cause of your bug. You will have to continue searching with firebug further to get to the actual control inside the section control that is the root cause.

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You can test the translation files you create and upload into  by clicking the  test  icon on the Internationalization screen or you can use the  &locale URL parameter  to initialize the form with other languages. See Multi Language Support for details on creating translations and testing locale translations ..

Purging form/flow test data

Refer to this article for a quick easy way to purge your test data (tasks and submissions).

Internet Explorer Compatibility Mode

If your Forms and flows do not look or work correctly in Internet Explorer, Compatibility View may be turned on. Refer to this article for more information.