Hi Fred Morin
Thanks for contacting Syncfusion support.
We have checked the reported issue with “when i enter edit mode the pop up screen covers the cells making it invisible” and it is working fine from our side. We have tested a sample with 500 rows and edited the lower item, but cell is visible at top of editor keyboard as expected and please find the below screenshot for the same.
We have prepared a sample for the same and please find the sample from the below link.
In case, if you are still facing the issue from your side. Please modify the attached sample to reproduce the issue which will be helpful for us to validate the issue and provide you the solution at earlier.
Regards
Vigneshkumar R