WebApp Import CSV over 1500 items

Reported by Al Marks:
"I tried 500, 1000, and the whole 45000. 500 it seems to do fine and tells me that its began the process. At 1000 the import button just constantly spins and does not inform me that the upload attempt has begun however it apparently still does the upload. Lastly when trying to upload the entire 45000 it just doesn't work unfortunately."