Finally got it:
You need to modify the file filter for HTML files to include the .pt extension in Tools > Options > IDE Options.
Вопрос
How do I configure the list of file extensions for syntax highlighting in PyScripter?
In particular I like to include Zope Page Template files (ZPT) with extension .pt to the list of HTML files to show proper syntax highlighting.
Решение
Finally got it:
You need to modify the file filter for HTML files to include the .pt extension in Tools > Options > IDE Options.