Bug report

Regression introduced in R2 2020. Possibly related to #5467

Reproduction of the problem

1. Set up a ComboBox that uses virtualization:

<input id="orders" style="width: 100%" />

<script>
    $(document).ready(function() {
        $("#orders").kendoComboBox({
            dataTextField: "ProductName",
            dataValueField: "ProductID",
            virtual: {
                itemHeight: 26,
                valueMapper: function(options) {
                    $.ajax({
                        url: "Home/Orders_ValueMapper",
                        type: "GET",
                        dataType: "json",
                        data: convertValues(options.value),
                        success: function (data) {
                            options.success(data);
                        }
                    })
                }
            },
            height: 520,
            dataSource: {
                transport: {
                    read: {
                        url: "Home/Virtualization_Read",
                        dataType: "json" 
                    }
                },
                schema: {
                    model: {
                        fields: {
                            ProductID: { type: "number" },
                            ProductName: { type: "string" },
                        }
                    },
                    data: "Data",
		    total: "Total"
                },
                pageSize: 80,
                serverPaging: true,
                serverFiltering: true
            }
        });
    });

    function convertValues(value) {
        var data = {};

        value = $.isArray(value) ? value : [value];

        for (var idx = 0; idx < value.length; idx++) {
            data["values[" + idx + "]"] = value[idx];
        }

        return data;
    }
</script>

2. Return an empty collection:

public ActionResult Virtualization_Read([DataSourceRequest] DataSourceRequest request)
{
    return Json(GetProducts().ToDataSourceResult(request), JsonRequestBehavior.AllowGet);
}

public IEnumerable<Product> GetProducts()
{
    var products = Enumerable.Range(0, 0).Select(i => new Product
    {
        ProductID = i,
        ProductName = "ProductName" + i
    });

    return products;
}

3. Focus the ComboBox input and press Down Arrow

Current behavior

A request to the Read action is sent with the following parameters:
http://localhost:54962/Home/Virtualization_Read?take=0&skip=NaN&page=NaN&pageSize=0&filter%5Blogic%5D=and

The NaN value of the parameters: skip=NaN&page=NaN causes a server error:

Input string was not in a correct format.
...
[Exception: NaN is not a valid value for Int32.]

Expected/desired behavior

No exception should be thrown. In versions prior to R2 2020 a request is not sent to the server on pressing Down arrow key.

Environment

• Kendo UI version: 2021.2.511
• jQuery version: x.y
• Browser: [all]

Bug report

The ComboBox doesn't reset its default state when removing the selected items with Ctrl+A && pressing the Delete/Backspace button.

This bug is a regression from the 2018 R3 version.

Reproduction of the problem

1. Open this Dojo project
2. Select the ComboBox and enter "Hanari Carnes", then select the first element
3. Clear the value of a field in one step (press Ctrl+A then Delete/Backspace button). The dropdown of the ComboBox will open.
4. Select the first element in the list - "Vins et alcools Chevalier".
5. The dropdown closes and no item is selected

Current behavior

When selecting the first element in the list, the Combobox closes without adding a value to the ComboBox input.

Expected/desired behavior

When the "Vins et alcools Chevalier" value is selected , the value should be added in the ComboBox input and the dropdown should close.
Here is a Dojo demonstrating the correct behavior.

Environment

• Kendo UI version: 2019.3.1023
• jQuery version: x.y
• Browser: [all]

Bug report

The input field of the Combobox is being shifted when a "position: absolute" style is set on its initial element.

Reproduction of the problem

1. Open this Dojo example
2. Run it and see the floating "Rib Knit" text which is the input field of the Combobox

Current behavior

The input field of the Combobox is shifted when "position: absolute" style is set on its initial element.

Expected/desired behavior

When setting "position: absolute" style on ComboBox initial element the whole component should be shifted according to the set "top, bottom, left, right" parameters.

A possible workaround that could be applied in the above linked Dojo is the following one:
$("#comboboxA").getKendoComboBox().input.css("position", "static");

Here is the modified Dojo with correctly working Combobox with "position: absolute" style is set on its initial element.

Environment

• Kendo UI version: 2019.3.917
• jQuery version: x.y
• Browser: [all]

Bug report

ComboBox with filtering option set to "contains".

Search for the last element in ComboBox dropdown and select it. Delete the selected item with mouse selection and "Delete" button. The dropdown will open again. Select the first element in the dropdown. It will close and no data will be selected. If we repeat the scenario and instead of selecting the first element, we select another one, everything is working properly.

This is regression introduced in 2018 R1 SP1

Reproduction of the problem

1. Open this Dojo and run it
2. Select the ComboBox and enter "rib", then select "Rib Knit"
3. Unfocus the ComboBox and then focus it again
4. Using the mouse select the "Rib Knit" text and delete it. The dropdown of the ComboBox will open.
5. Select the first element "Cotton".
6. The dropdown closes and no item is selected

Current behavior

Please check this demo video.

Expected/desired behavior

Please check this demo video

Environment

• Kendo UI version: 2019.2.514
• jQuery version: x.y
• Browser: [all]