ScrollArea scroll state modified by sibling textedit

[sphaerophoria]

Describe the bug If I add a text edit, then a scroll area, typing in the text edit moves the position of the scroll area. E.g.

To Reproduce Sample program...

use eframe::egui::{self, ScrollArea};

fn main() {
    let native_options = eframe::NativeOptions::default();
    eframe::run_native("My egui App", native_options, Box::new(|cc| Box::new(MyEguiApp::new(cc))));
}

#[derive(Default)]
struct MyEguiApp {
    input: String,
}

impl MyEguiApp {
    fn new(cc: &eframe::CreationContext<'_>) -> Self {
        // Customize egui here with cc.egui_ctx.set_fonts and cc.egui_ctx.set_visuals.
        // Restore app state using cc.storage (requires the "persistence" feature).
        // Use the cc.gl (a glow::Context) to create graphics shaders and buffers that you can use
        // for e.g. egui::PaintCallback.
        Self::default()
    }
}

impl eframe::App for MyEguiApp {
   fn update(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {
       egui::CentralPanel::default().show(ctx, |ui| {
           ui.text_edit_singleline(&mut self.input);
           ScrollArea::vertical()
               .show(ui, |ui| {
                   for i in 0..100 {
                       ui.label(format!("test{}", i));
                   }
               });
       });
   }
}

Expected behavior Scroll area stays fixed when typing in adjacent boxes

Desktop (please complete the following information):

• OS: Linux, observed on both Ubuntu 20.04 and Arch Linux

Additional context

• Typing when the text edit is not selected does not move the scroll area
• I tried a few workarounds thinking that it might be related to internal state from the text edit leaking into the scroll area
  • Adding id sources to the text edit or the scroll area didn't seem to help
  • Wrapping the text edit within a sub-ui with ui.allocate_rect also doesn't resolve the issue

[sphaerophoria]

I'm unsure if this is by design or a mistake.

It looks like the problem is that in the textedit we call ui.scroll_to_rect() when the text changes. This sets the frame state for the whole context which is read back in the scroll area

[emilk]

This is a bug - it should only scroll the parent scroll area, but there is no logic in place to ensure this. Good catch!

[Barugon]

I have run into this bug. Is there a fix for it?

[edit] Or perhaps a workaround?

[Barugon]

Looking at this line, it seems to me that a TextEdit would not scroll into view if it was completely outside the clip area. Therefore, this code is really of no use (other than to cause havoc).

[Barugon]

Confirmed. Using the OP's code, I moved the TextEdit into the scroll area, gave it focus, scrolled it out of view, typed some stuff and it did not scroll into view.

[edit] The TextEdit will only scroll into view if it's partially visible. Is this intended behavior?