DescriptionTip and ParameterInfo provide only a maximum width
But there's no MaxHeight property; and if the help text is quite long, the popup window would take a lot of room.
I already 'fixed' that for the ParameterInfo. I added an own control, which provides a scroll viewer, and put HtmlContentProvider.GetContent into the ContentPresenter.
I would try this for DescriptionTip, too, but I'm afraid this would not work.
I wonder if you guys couldn't add support for a MaxHeight property and a ScrollViewer; and actually for both DescriptionTip and ParameterInfo.