Bug report:
MultiColumnComboBox select event is triggered when the dataSource has items with empty text
Reproduce problem:
https://dojo.telerik.com/exAtuTUJ/6
The steps to reproduce this problem:
1. click the dropdown to show options
2. Click anywhere on the document(You will see the alert message, it prompts for trigger event).
Current behavior:
Trigger event anywhere you click on a document.
Expected behavior:
Trigger event only when you click the values in the MultiColumnComboBox component.
Environment:
### Bug report
The MultiColumnComboBox is initialized without a specified value. When the user focuses on the widget and leaves it without selecting or entering an option, the "cascade" event is fired.
### Reproduction of the problem
1) Create a MultiColumnComboBox and initialize it without a value;
2) Subscribe to the "cascade" event after the initialization of the widget;
3) Focus the input;
4) Leave it;
5) The "cascade" event is triggered on "blur".
A Dojo sample for reproduction: https://dojo.telerik.com/EViKaXaZ
### Expected/desired behavior
The "cascade" event should fire when changing the widget's value via API or user interaction.
### Environment
* **Kendo UI version: 2021.3.914
* **jQuery version: 1.12.4
* **Browser: [all]
When virtualization is enabled in the MultiColumnComboBox and the user scrolls down in the popup to load new items sometimes an item that is not actually hovered is highlighted as hovered (the 'k-hover' class is applied).
Sometimes random item that is not hovered has the 'k-hover' class.
screencast - https://www.screencast.com/t/KXhG7SBkE6
Items that are not hovered should not have the k-hover class and should not be highlighted as hovered.