On 22 Sep 2016, at 2:32, David Green wrote:

If it’s at all possible, it would also be quite handy for the Find dialog to use a different colour for special characters like backslashes, or * ? (), etc. with regexes.

If you hold option and Check for Updates then beta 12.15 will syntax highlight both the search and replace strings (when regular expression is enabled).

For the search string it uses the Regular Expressions (Oniguruma) grammar in the TextMate bundle and for the replace string, the Format String grammar is used (also from the TextMate bundle).

The coloring comes from the Mac Classic theme but this can be changed via the UIThemeUUID defaults key.

The “show invisibles” feature is unfortunately a bit more involved, since we are only allowed to add “attributes” to the edited string (during editing), and there doesn’t seem to be any attribute to make invisible characters visible.

We can however do this when the field is inactive, since here we are allowed to change the string.