Describe the bug
multiple false still allows more than one files dropped on windows

To Reproduce
https://stackblitz.com/edit/gvptz7-ltakhv?file=src%2Fmain.vue

Drop more than one file on windows
Expected behavior
it should not be allowed

New Native Vue DropDownTree Component

Describe the bug
Currently only item template is supported and the user can't add custom components instead of items

Expected behavior
The user is able to add templates for the header for the footer and all the content of the drawer.

Temporary workaround is to use one dummy item and its template - https://stackblitz.com/edit/lfvpga?file=src%2Fmain.vue

Add active class to the column menu icon once something in it is different from default

Currently we recommend using custom class on the header(https://www.telerik.com/kendo-vue-ui/components/grid/columns/column-menu/#toc-styling-the-column-menu-icon), yet not visualising that the menu is populated seems like a UI misleading issue when using the component so we should add it by default

Describe the bug
Locked and resized columns leave a small gap between the columns when scrolling is performed

To Reproduce
Steps to reproduce the behavior:
https://stackblitz.com/edit/mzxqs7-hy29kw?file=src%2Fmain.vue
lock both first and the second column from the column menu
resize the first column
scroll the columns

Curent -
A tiny gap is visible between the first and the second column

Describe the bug
The items inside the popup of the Multiselect are not correctly visualized when scrolling the data. The issue can be easily observed in scenarios where the page size and the total of records are close numbers.

The issue is that while scrolling, the Multiselect scrolls but the actual contents of the popup don't move until the scroll bar is more than halfway down.

To Reproduce

1. Open this project
2. Start scrolling the items in the MultiSelect

Expected behavior
With the move of the popup scroller down, the data should be scrolled too, no matter if the scroller has reached its middle position or not.

Screenshots
The screenshot is from the linked above example. The items displayed in the popup window should be around "Item 50"

Currently, the Kendo UI for Vue Native DropDownList doesn't have the valuePrimitive property which is available in the:

• Angular DropDownList - https://www.telerik.com/kendo-angular-ui/components/dropdowns/api/DropDownListComponent/#toc-valueprimitive 
• and the jQuery DropDownList - https://docs.telerik.com/kendo-ui/api/javascript/ui/dropdownlist/configuration/valueprimitive 

Providing such property for the Native Vue DropDownList will be useful in different use-case scenarios. 

In the vue native grid, the inputs rendered in the filter row don't have a title or accessible name. This would make it nearly impossible for someone using a screen reader to understand what each field means. In order to comply with WCAG 4.1.2 (Name, Role, Value) please add a title and/or aria-label/labelledby attribute to these inputs. 

The jquery grid has the aria-label and title populated with the column name. I think it'd be even more useful if the label said "Filter by {columnName}".