Allow holding shift on ScrollAreas with horizontal scrolling disabled

[doonv]

Describe the bug
Pressing/Tapping Shift after a ScrollArea::new([false, true]) (Vertical Scrolling Only) was opened causes scrolling via the scroll wheel to no longer work.

To Reproduce
Steps to reproduce the behavior:

1. Create a ScrollArea with only vertical scrolling.
2. Scrolling works
3. Press Shift
4. Scrolling doesn't work

Expected behavior
The ScrollArea always scrolls vertically regardless of if Shift was pressed or not.

Desktop (please complete the following information):

• OS: Kubuntu 23.10
• Browser: Not using a browser
• Version: bevy_egui = "0.23.0", egui = { version = "0.23.0", default-features = false, features = ["bytemuck"] }

Additional context
I am using egui in bevy using bevy_egui.

[doonv]

This issue is most likely caused by #663 as that is when horizontal scrolling was added. (Which uses Shift to know when to horizontally scroll)

[emilk]

is this bug about not being able to scrol while holding down shift, or not being able to scroll after tapping shift once and then releasing it?

[doonv]

@emilk It's about not being able to scroll after tapping shift once.

[emilk]

I can't reproduce. Sounds like a problem of sticky modifier keys on your system.

Does egui report the SHIFT modifier to be pressed even after you released it? (ctx.input(|i| dbg!(i.modifiers));)

Please take a look at crates/egui-winit/src/lib.rs and see how modifiers.shift is updated - perhaps WindowEvent::ModifiersChanged is not working properly?

[doonv]

It might be a bevy_egui issue. I'll try out doing it with eframe (or whatever you use to make native egui applications)

[emilk]

Check out this repository and run cargo run -p egui_demo_app. If there is no problem then yes, it is a bevy_egui problem.

[doonv]

Yeah I can't reproduce the bug when using cargo run -p egui_demo_app.

I also did ui.input(|i| i.modifiers.shift) and, as I suspected it continued being true after i realised the shift key. So I'm closing this and making a bevy_egui issue instead.

[doonv]

I'm reopening this for a different reason. Because even if Shift is being held, it shouldnt affect the scrolling if horizontal scrolling is disabled.