When setting the Checkbox component to disabled while the form is marked as touched, the k-invalid class is applied to the checkbox control.

That's because of the implementation of the isControlInvalid property:

public get isControlInvalid(): boolean {
    return this.control && this.control.touched && !this.control.valid;
}

According to the Angular source code:

    /**
     * A control is `valid` when its `status` is `VALID`.
     *
     * @see {@link AbstractControl.status}
     *
     * @returns True if the control has passed all of its validation tests,
     * false otherwise.
     */
    get valid(): boolean;

So valid() returns false when `status` is DISABLED.

The `isControlInvalid`property should better implemented like this:

public get isControlInvalid(): boolean {
    return this.control && this.control.touched && this.control.invalid;
}

Please check this Stackblitz: https://stackblitz.com/edit/angular-dznoe1xj?file=src%2Fapp%2Fapp.component.ts

Hello,

I tried to implement this new feature : https://www.telerik.com/kendo-angular-ui/components/grid/scroll-modes/virtual#controlling-the-expanded-state-of-all-root-level-groups

You can see in the demo that if you remove all grouping, the content is now limited to 50 lines instead of displaying the whole 1000.

I found a workaround by expanding all before removing the grouping but it is not very user friendly.

If you can patch it ASAP that would be great. 

And thank you to finally have pushed this long awaited feature !