<TelerikButton OnClick="@BugHandler">Enable second pane (bug)</TelerikButton>
<br /><br />

<TelerikSplitter Orientation="SplitterOrientation.Vertical" Height="200px">
    <SplitterPanes>
        <SplitterPane>
            <div>First pane</div>
        </SplitterPane>
        @{
            if (EnablePane2)
            {
                <SplitterPane Collapsible="true">
                    <div>
                        Second pane
                    </div>
                </SplitterPane>
            }
        }
    </SplitterPanes>
</TelerikSplitter>

<br />
<TelerikButton OnClick="@WorkaroundHandler">Enable second pane (workaround)</TelerikButton>
<br /><br />

<TelerikSplitter Orientation="SplitterOrientation.Vertical" Height="200px">
    <SplitterPanes>
        <SplitterPane>
            <div>First pane</div>
        </SplitterPane>
        <SplitterPane Collapsible="@Collapsible2" Resizable="@Resizable2" Size="@Size2" Collapsed="@Collapsed2">
            <div>
                Second pane
            </div>
        </SplitterPane>
    </SplitterPanes>
</TelerikSplitter>

@code {
    bool EnablePane2 { get; set; } = false;

    bool Collapsible2 { get; set; }
    bool Resizable2 { get; set; }
    string Size2 { get; set; } = "0px";
    bool Collapsed2 { get; set; } = true;

    void BugHandler()
    {
        EnablePane2 = true;
    }

    void WorkaroundHandler()
    {
        Collapsible2 = true;
        Resizable2 = true;
        Size2 = "";
        Collapsed2 = false;
    }
}