Hi,
It works actually but you need some CSS and maybe JS to apply. For example, here is the configuration of the web part:
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And after clicking on the empty search in the HTML you can see that CSS class and Title fields are actually updating.
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So what you'd need to do is:
- Style input field with some CSS error class
- Display Title message
And by the way, to avoid the page reload, you can use Update panel:
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