Using scrollwheel on a (modal) Popup moves application content

If I have an application with an flickable item and a (modal) popup, using the scrollwheel of my mouse on the Popup scrolls the application flickable item (see attached code). For a non-modal popup this behaviour would be ok for me, but for a modal popup I wouldn't expect this.

If the popup itself contains a Flickable too (not shown in the attached code), the content of both Flickables will move. Looks quite nice, but I would prefer that only the popup content moves.