wpf - Tooltip on scrollviewer in documentviewer in case of deferred scrolling -

i want show tooltip on scrollviewer on page scrolling shows current page number in asked here- tooltip on scrollviewer in documentviewer.

i have implemented answer after making changes in proposed solution face problem. if write in scroll_changed event if (mouse.leftbutton == mousebuttonstate.pressed) works fine if have deferred scrolling enabled on custom document viewer, popup(tooltip) never appears..:(

is there workaround it??