If you add a context menu to a textbox it disables the box. I've asked about this previously in a support call but was told it's not likely to be supported as there's no demand for it. It would allow for excel like interaction where you can select a number of textboxs on mobile and right click/long click to get a menu,
Adding our context menu to a textbox should not disable it. I verified that in the following test, using the latest Kendo UI release: http://dojo.telerik.com/AMIxe Let me know if I missing something.