I am afraid that your question is a bit unclear. I assume that by "combobox" you mean "dropdownlist" (the widget shown on the attached screenshot).
The reason for different UI is that the DropDownList widget receives platform specific styling when initialized in a Kendo UI Mobile application in order to provide a better touch experience to the user. I am afraid that currently this behavior cannot be prevented. Please accept my apology for the inconvenience caused.
One possible workaround is to use the standard select element. In this way the browser will generate native picker if such is supported.
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