Display NULL while editing a NULL cell

[seancolsen]

Current behavior

1. Find a NULL cell.
2. Double click to enter edit mode.
3. Observe that NULL no longer displays when in edit mode, leaving the user with no way to distinguish NULL from empty string while editing.

Desired behavior

1. Double click to enter edit mode on a NULL cell.
2. NULL appears after the cursor, styled the same as when viewing the cell in select mode.
3. Begin entering text.
4. Observe that NULL disappears, being replaced by the text entered.
5. Delete all text entered.
6. Observe the cell to be blank (no NULL displayed) indicating the value is an empty string.

Notes

• In edit mode, the user won't have a way to set the cell to NULL. That's okay for now. Add context menu to set cell value to NULL #930 and Add keyboard shortcuts for setting a cell to NULL #936 will give users the capability to set a cell to NULL (but only from select mode).
• We should also style the NULL value the same in edit mode as it is styled in select mode. See discussion within What's the best terminology to use in our UI for the concept of NULL? #778 to learn more about our thinking on style.

See also

• See Blur via keyboard after entering edit mode on a NULL cell should cancel edits #929 for a bug that you may hit while working on this ticket. (Note that you can still preserve your NULL value by clicking outside the cell instead of pressing Esc.)

Additional context

See NULL Value Specs, scenario 2b

[gagan2005]

I would like to work on this

[seancolsen]

Thanks @gagan2005! I've assigned this ticket to you. Let us know if you need any help. Feel free to ask questions here or in Matrix (our chat system).

[gagan2005]

#961