Should widgets scroll to highlighted item when resized?

[TomJGooding]

I've been hesitant to create an issue for this, but should widgets automatically scroll to the highlighted item after being resized? Or is this something that is expected to be handled by the developer?

The below example with an OptionList hopefully demonstrates what I mean. Obviously resizing the terminal could also cause the highlighted item to go out of view.

from textual.app import App, ComposeResult
from textual.containers import Horizontal
from textual.widgets import Footer, OptionList, Placeholder


class ExampleApp(App):
    BINDINGS = [
        ("t", "toggle_panel", "Toggle Panel"),
    ]

    CSS = """
    Placeholder {
        width: 2fr;
        display: none;
    }

    .show-panel {
        Placeholder {
            display: block;
        }
    }
    """

    def compose(self) -> ComposeResult:
        with Horizontal():
            yield OptionList(
                *[
                    f"This is option {i} which is long and might wrap when the widget is resized"
                    for i in range(100)
                ]
            )
            yield Placeholder()
        yield Footer()

    def on_mount(self) -> None:
        options = self.query_one(OptionList)
        options.highlighted = 50

    def action_toggle_panel(self) -> None:
        self.toggle_class("show-panel")


if __name__ == "__main__":
    app = ExampleApp()
    app.run()

[github-actions]

We found the following entries in the FAQ which you may find helpful:

• No widget called TextLog
• How do I center a widget in a screen?

Feel free to close this issue if you found an answer in the FAQ. Otherwise, please give us a little time to review.

This is an automated reply, generated by FAQtory

[willmcgugan]

It probably should... I can't think of any reason why not scrolling would be more desirable. Should be a simple fix. Calling scroll_to_highlight on the resize event.

[darrenburns]

I could see reasons why I wouldn't want this. If I've got the highlighted item scrolled out of view, it might suggest I'm reading other items in the list. What is highlighted doesn't always correspond to where my attention currently is. If I resize in this case, I definitely would want to try and keep my current reading position in the list (in other words: don't scroll).

[TomJGooding]

@darrenburns Fair point. I'm usually navigating with the keyboard, so hadn't considered if you'd scrolled away from the highlight using the mouse.