Hi Cemil,
Thanks for contacting Syncfusion support.
We have checked your reported case “quickInfo popup always open above” and as per the Scheduler architecture quickInfo popup position has been calculated based on the available space between the clicked cell and browser. Kindly share whether the quick popup opens on top of the clicked cell at your end by depicting the issue in a video or image to understand the issue and proceed further.
Regards
Alagumeena.K