Looking for the magic to make a PropertyManagerPageNumberBox control behave like most standard SolidWorks functionality where the user can enter units and / or formulas. From what I can see it looks like PropertyManagerPageNumberBox.Text says it calls the IPropertyManagerPage2Handler5::OnTextboxChanged method where you can deal with the text that was entered. But I'm that handler was superseded and I'm currently using the IPropertyManagerPage2Handler8 implementation and it never gets called. so I'm not sure if that's a documentation error or what. This should not be that hard to do but I can't seem to stumble onto the magic. If I use a text box I can grab the string and use the iUserUnit::ConvertToSystemValue Method which what I thought I would need to do.