Enable mouse wheel scrolling while dragging inside a ScrollArea

[rustbasic]

Enable mouse wheel scrolling while dragging inside a ScrollArea

Problem

When the pointer button is held down and a widget inside a ScrollArea is being dragged (e.g. selecting text in TextEdit), mouse wheel scrolling does not work. This happens because ScrollArea only processes mouse wheel scrolling when ctx.dragged_id().is_none(), i.e. when no widget is currently being dragged.

Change

Relax the wheel-scrolling gating condition so that wheel scrolling is allowed whenever the pointer is over the scroll area (or when background-drag scrolling is active), even if another widget is currently being dragged.

Concretely, we replace the dragged_id().is_none() requirement for the mouse wheel path with:

• pointer_over_outer = ui.rect_contains_pointer(outer_rect) || is_dragging_background
• Use pointer_over_outer to decide whether to apply wheel scrolling

Result

• Wheel scrolling works while dragging/selecting within widgets inside a ScrollArea (notably TextEdit).
• This matches common desktop editor behavior: drag-select while wheel-scrolling to extend selection.

Notes / Potential behavior change

This enables wheel scrolling during any active drag (not only TextEdit), as long as the pointer is over the ScrollArea. If maintainers prefer limiting this to specific widgets (e.g. only text selection), we can follow up with a more targeted approach (e.g. an explicit option/flag).

Files changed

• scroll_area.rs (wheel scrolling hover gating logic)

[github-actions]

Preview available at https://egui-pr-preview.github.io/pr/7919-patch171
Note that it might take a couple seconds for the update to show up after the preview_build workflow has completed.

View snapshot changes at kitdiff