I had to add Windows Forms chart control to a WPF app. I hosted it using WindowsFormsHost. Things worked fine until I noticed that there is no scroll bar when I add several controls.
First, I tried to add WPF scrollbar to parent panel of WindowsFormsHost but it behaved weirdly. The scrolled WinForms controls goes out of window bound to other windows! And it is drawn on top other windows. In other words, when scrolled, it floated freely as if there is no window.
Later, I tried to add a WinForms panel (any type of panel will work) to WindowsFormsHost and add scroll bar to the WinForms panel. It worked! Yeah!
I realized that if you need to scroll WinForms controls, you need to use WinForms scroll bar.
Note that WPF scroll bar is outside of WindowsFormsHost and the WinForms control is inside of WindowsFormsHost. Using WPF scroll bar to scroll WinForms control is nothing short of begging for trouble.