This issue is occurring in Chrome, I have not tried other browsers.
The issue can be observed in demo http://demos.telerik.com/kendo-ui/autocomplete/serverfiltering
Note the minLength: 3 setting.
Type in "che" per the hint. Developer tools network activity will show the $filter parameter as [ substringof('che',tolower(ProductName)) ]. All fine and good.
Now clear "che" by clicking on clear (x). The network activity tab will show a Products call back with a $filter parameter [ substringof('',tolower(ProductName)) ]. The minLength setting was obviously ignored and the filter actually pulls _all_ the data from the remote source. In the example it is 77 items. For real world scenarios an unfiltered query could return an application destroying amount of data. Despite pulling all the data, no suggestions are shown -- I presume because at this point the minLength is honored and thus no suggestions
Q: How can I prevent an unfiltered query when clear clicked ?
Q: How can I force the autocomplete data source to have no items when clear is clicked ?