selectionInProgress

True only while the finger is still down on the long-press drag that is building the selection; false the moment it lifts.

This is the flag a selection menu should gate on. isSelectionActive deliberately stays true after the finger lifts (it keeps the page from drifting while the user acts on the words), so it cannot distinguish "still choosing" from "chosen". A popup shown while this is true covers the very words the finger is trying to reach; PdfSelectionMenu waits for it to drop.