Warning X marks are confusing
@aday
Submitted by Allan Day Link to original bug (#734796)
Description
When a cell can't be filled, a red X is shown in the cell. This has a few problems:
- It doesn't look like you can enter a number into the cell.
- If you put a number into the cell, you no longer see the warning.
- The X looks bad.
Changing the background colour of the cell would be a better approach for showing the warning.
Version: 3.13.x