I'm using the Tkx module on windows. I want to select some text lines by software. In according to the documentation, all selected text has the "sel" tag added. When i select text by mouse, i see the tag is added to the selection. But when i add this tag by code, i don't see the selection in a text widget. All lines look default despite they state is "selected". How do i make software selected text look like selected by mouse?