8556: flashes when moving between two fields

[grisendo]

From http://bugs.jqueryui.com/ticket/8556

[tjvantoll]

Hi @grisendo ,

Thanks for taking the time to contribute to jQuery UI. We have the following requirements of pull requests before we can review them.

• Include a unit test to ensure the fix works and prevent against regressions.
• Ensure code adheres to our style guide. (We realize the code around this doesn't necessarily follow these guidelines, but we use it for all new code.)
• Ensure commit messages adhere to our commit message style guide.

I'm going to close this PR for now. If you would like to address these points please send a new PR.

Thanks.