src/js/pannellum.js
function onDocumentPointerUp(event) {
    if (event.pointerType == 'touch') {
        var defined = false;
        for (var i = 0; i < pointerIDs.length; i++) {
            if (event.pointerId == pointerIDs[i])
                pointerIDs[i] = undefined;
            if (pointerIDs[i])
                defined = true;
        }
        if (!defined) {
            pointerIDs = [];
            pointerCoordinates = [];
            onDocumentTouchEnd();
        }
        event.preventDefault();
    }
}
function onDocumentPointerUp(event) {
    if (event.pointerType == 'touch') {
        var defined = false;
        for (var i = 0; i < pointerIDs.length; i++) {
            if (event.pointerId == pointerIDs[i])
                pointerIDs[i] = undefined;
            if (pointerIDs[i])
                defined = true;
        }
        if (!defined) {
            pointerIDs = [];
            pointerCoordinates = [];
            onDocumentTouchEnd();
        }
        event.preventDefault();
    }
}
Event handler for touch ends in IE / Edge.
@private
@param {PointerEvent} event - Document pointer up event.