The site suffers from a lack of input validation pretty much everywhere. I believe there is a single check in the settings modal, but there should be more checks to make sure that inputs make sense. Some examples:

• Tasks must have a name (no empty names or names with only whitespeace)
• Tasks cannot be due before the current date
• Tasks cannot have a negative duration, effort, priority (eventually), or number of chunks
• Chunks cannot be manually assigned after their parent task's due date or before the current date
• Anywhere where a range of dates/times can be edited, the end date/time must be after the start date/time