The close icon is vertically misaligned

Steps to reproduce:

1. Go to https://demos.telerik.com/aspnet-ajax/multicolumncombobox/overview/defaultcs.aspx

2. Enter any text in the filter

3. See that the X icon is misaligned 

When search dropdown is open in MultiColumnComboBox and you scroll the page (e.g. by mouse wheel) the dropdown is immediately closed which is quite inconvenient.

Both Combobox and DropDownList keep the dropdown opened when you are scrolling the page.

Could you fix it?
Any temp workaround?