Thanks for the feedback.
Although the data attributes and the constructor options are interchangeable in general, the icon
setting is not recognized in the options parameter of the button
(we will fix that for the final release). It is an overlook on our side.
Since all mobile widgets support event handlers in the constructor options (and pass similar parameters to the event handlers), we are going to document this in a general Kendo UI Mobile help topic.
What is also coming for the final release is declaring events via data attributes.
the Telerik team
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