I am using a modal popup extender to show part of my web page as a popup. When the web page is at the top the popup looks fine, it appears in the middle of the page and can be dragged around the page with the drag handle.
When the grid view on the page shows more records, obviously this means the user must scroll down the page to see other records. This is where the problem starts.
If the popup is visible and the page is scrolled down the popup over takes the page and disappears off the bottom of the page.
If the user has already scrolled down the page then when the popup is triggered it will already off the bottom of the page only to be seen again when scrolled up.
I can half solve this by changing the reposition mode to RepositionOnWindowResize, this has the effect of when the user is at the top of the page and scrolls down the popup stays in place, but if the user has scrolled to the bottom of the page and triggers the popup it doesn't appear at all.