It would also be useful to be able to set some completely custom text here (not just something out of the box). So for example the text could read "3 countries selected" instead of "3 items checked". Basically the ability to set the text directly (via a setter) and override the control's default text would be very useful. 

Hello Marin,

Thank you for the workaround! I tried it, and it works so far, but IMO it has 4 disadvantages:
1.	The custom message shows the checked items, instead of the selected entries (as they are listed by default), which is not always the same.
2.	The custom message is not displayed on the initial pageload when items are preselected, and it gets lost after a postback.
3.	The custom message is empty when the user deselects all items manually.
4.	The custom message does not appear when the user clicks on the Check All’ button.

Here’s my solution for 1. – 3. Put the following code into the <script> block:


function set_fakeInputText (sender, args) {
    var entries = sender.get_entries();
    if (entries.get_count() > 3) {
        var text = entries.get_count()) + “ entries selected”;
        $telerik.$(sender.get_element()).find(".rddtFakeInput").text(text);
    }
}

function OnClientLoad(sender, args) {
    set_fakeInputText(sender, args);

    var tree = sender.get_embeddedTree();
    tree.add_nodeChecked(function (tree, eventArgs) {
        set_fakeInputText(sender, eventArgs);
    });
}


I could not find a solution for 4., because there seems to be no OnClientCheckAllButton handler. Or did I miss something?

However, I agree with Dan that this feature should be built in.

Thanks. will check it out. I do think though that built in support should be added just like in the combo control