Text editing single character in 2.10 - default

[Blighty]

1) Select the text layer
2) Select the Text Tool and click on the text
3) Delete the 9, type 4
4) Select another tool eg Move Tool, or Measure Tool
Done, text retains colour and size.

Note:
The tool options below the tool box is "global" for that text.
The on canvas editing is for selected characters only.