Hi Hugo,

We really apologize for the inconvenience, the entire time we have been focusing on the items with high demand from customers and could not get to this point. Today, however, we were able to take a look and find a fix for it. It will be released it in 2025 Q3 (mid August).

I am sharing a workaround below if you wish to use it until then.

Workaround

Add the following script to ContentPage or MasterPage after the ScriptManager declaration:

<script>
    (function () {
        try {
            var original_clearButtonMouseDown = Telerik.Web.UI.RadDropDownTree.prototype._clearButtonMouseDown;

            Telerik.Web.UI.RadDropDownTree.prototype._clearButtonMouseDown = function (e) {
                original_clearButtonMouseDown.call(this, e);

                // Add your override that will trigger the postback
                var cancelClicking = this._onClearButtonClicking();

                if (this.get_enabled() && !cancelClicking && this._autoPostback) {
                    this._fireServerEvents = true;
                    this.updateClientState();
                    this._postback();
                }
            }
        } catch (e) { }
    })();
</script>

Thank you for your understanding!

Regards,
Attila Antal
Progress Telerik

Hi,

Thank you for the feedback, Greg - I have increased the priority of the bug as per your request.

Regards,
Vessy
Progress Telerik

Hi Jesper,

This bug is still not resolved in favor of items with higher priority. I have increased the priority of this one now, so it will appear upper in our developer-s To-do list. Once the bug is resolved the status of this item will be updated immediately, so you can follow it in order to be notified about any updates.

Regards,
Vessy
Progress Telerik