I've attached a sample that uses a custom attached event that gets raised on the XamRibbon when the ToolTipOpening is being raised for something within the xamRibbon. In this way you can handle the event and decide there if you want to prevent the tooltip and you won't need to define a style per tool type.

I managed to work around this limitation by adding the following markup:

                    <Style TargetType="{x:Type r:ButtonTool}">
                        <EventSetter Event="ToolTipOpening" Handler="tool_ToolTipOpening" />
                    </Style>

which of course needs to be repeated for each tool type used.

Its probably because the tools themselves are not displayed within the menu but are represented by menu items. I added this to the notes for the issue that was submitted. It seems that MS conditionally shows the tooltips - e.g. it does show them for tools that have a shortcut. Since the tool itself doesn't really know this condition the ultimate fix for this issue may be to add a property that determines when the tooltip is shown or allow utilization of the ToolTipService.IsEnabled.

Thanks, this solved the problem for footer items. However, when I tried reusing this on application menu items (adding a comparison to ToolLocation.ApplicationMenu), it didn't work.