Here are two (very likely related) bugs:

• A

  1. Begin with a unique column
  2. Edit cell, setting value to an existing value in the column.
  3. Observe error. Good.
  4. Refresh sheet via bottom right button. Notice error disappear. Good.
  5. Edit same cell again with same value.
  6. Expect to see the error as before.
  7. Instead, observe no error. Bad ❌
  8. Refresh via bottom button again. Expect the value to reset. Observe it to still display in the cell, even when selecting other cells. This is really bad! ❌
  9. Refreshing the whole page resets the value.

• B

  1. Make or find a "Date" cell.
  2. Verify that the "Time Format" for the column is set to "Short time 24 hr"
  3. Double-click the cell to enter edit mode.
  4. Manually enter the text "7:00 PM" and press Enter.
  5. Observe that the cell saves and displays as "19:00". Good.
  6. Double-click to enter edit mode again.
  7. Observe that the cell still displays as "19:00". Good.
  8. Press Escape to exit edit mode.
  9. Expect the cell to still display as "19:00".
  10. Instead, observe that the cell now displays as "7:00 PM". Bad ❌
  11. Select another cell and observe that the original cell returns to displaying "19:00". Good. But weird!!

To any community contributors considering picking this up: I expect this issue to be tricky. A fix will most likely involve a fair bit of refactoring and require a good understanding of the specific ways in which Svelte handles state.