TPC uses Wordpad to edit a Rich Text object externally, when the user presses the pencil icon in the bottom right of the Rich Text Box dialog. See Rich Text Box and RTF.
Beginning with Windows 11 update 24H2, the Wordpad program is no longer available. Microsoft didn't want to maintain it, so they removed it.
Correction
Beginning with TPC Desktop 2025, TPC uses Wordpad if it is available. If not, it uses MS Word, if it is available on your computer.
Editing RTF Manually
If neither of these is available, you can still edit the RTF text externally following these steps.
•Choose Export as RTF... and create the corresponding .rtf file
•Edit that .rtf file in your external RTF editor and save the file
•Choose Replace with RTF... and select the edited file
