cannot scroll using the < and > buttons when Overflow mode is Scroll

cannot tap on the dots button to open the drop-down on DropDown Overflow mode.

The issue happens in the PDF toolbar too.

When setting IsEnabled through binding, it does not work on items level, it works on toolbar level. Still the Isvisible property works on items level. 

<telerik:RadToolbar x:Name="toolbar" >
    <telerik:ToggleButtonToolbarItem Text="ToggleButton" IsEnabled="{Binding IsActive, Mode=TwoWay}">
        <telerik:ToggleButtonToolbarItem.ImageSource>
            <FontImageSource Glyph="{x:Static telerik:TelerikFont.IconBold}"
                        FontFamily="{x:Static telerik:TelerikFont.Name}"
                        Size="16" />
        </telerik:ToggleButtonToolbarItem.ImageSource>
    </telerik:ToggleButtonToolbarItem>
</telerik:RadToolbar>

I want to change the ButtonToolbarItem Tooltip to an other value then the Text-Property value.

Style ButtonToolbarItemView
<Setter Property="ToolTipProperties.Text" Value="..." /> 

and

xaml
ToolTipProperties.Text="..."

both have no effect. Tooltip keeps showing the Text value