Right-click context menu not working on drag and drop zone (0.31 -> 0.32 migration issue)

[Omustardo]

In 0.31, I can create a ui.dnd_drag_source, handle drops onto it, and then draw a right-click context menu on it using response.context_menu()

In 0.32, the drag and drop continues to work, but context menu doesn't open.

Minimal demo: https://github.com/Omustardo/egui_drag_and_drop_demo

The symptom is the same as #2471, where upgrading from 0.19 broke context menus for drag and drop items. The symptom feels similar to #2730 in which click and double click events on drag_and_drop zones aren't being passed through to the response. Both of those are old issues though, and this one is very clearly related to the 0.32 update.

From the 0.32 announcement, this issue seems most likely to be related to:

• "Popups, tooltips and menus have undergone a complete rewrite"
• "Memory::is_popup_open api now requires calls to Memory::keep_popup_open"

is_popup_open feels likely, though it would be odd for the context_menu call to not handle it internally. I gave it a quick attempt but didn't get anything working.

I've been poking at this for probably longer than I should and am hoping someone already knows the answer. I'll look into it more tomorrow.

[Omustardo]

I made an even more minimal demo:

• https://github.com/Omustardo/egui_drag_and_drop_demo/blob/main/0_31/examples/minimal.rs
  For this one, the exact same code is used for 0.31 and 0.32 unlike the other which had minor differences.

The new demo shows that all that it takes to reproduce this is a ui.dnd_drag_source that has a context_menu on the response.

---

I also dug into the code a bit. It's interesting that in both 0.31 and 0.32, the rectangle for the dnd_drag_source sets Sense::drag(). In order for the context_menu to open on right-click, the documentation says it needs to be able to sense clicks. This makes sense, but then it's unclear why it would work in 0.31. The code for Sense::drag has been unchanged since Feb 2024.

Perhaps there was a bug that allowed it to work which was fixed in 0.32?

---

Related code links:

• https://docs.rs/egui/latest/egui/struct.Ui.html#method.dnd_drag_source
• https://docs.rs/egui/latest/egui/struct.Ui.html#method.dnd_drop_zone
• https://docs.rs/egui/latest/egui/struct.DragAndDrop.html
• https://docs.rs/egui/latest/egui/response/struct.Response.html#method.context_menu

• egui/crates/egui/src/response.rs

  Lines 940 to 942 in fdcaff8

  	pub fn context_menu(&self, add_contents: impl FnOnce(&mut Ui)) -> Option<InnerResponse<()>> {
  	Popup::context_menu(self).show(add_contents)
  	}

• egui/crates/egui/src/containers/popup.rs

  Lines 502 to 632 in fdcaff8

  	/// Show the popup.
  	/// Returns `None` if the popup is not open or anchor is `PopupAnchor::Pointer` and there is
  	/// no pointer.
  	pub fn show<R>(self, content: impl FnOnce(&mut Ui) -> R) -> Option<InnerResponse<R>> {
  	let hover_pos = self.ctx.pointer_hover_pos();
  	let id = self.id;
  	if let OpenKind::Memory { set } = self.open_kind {
  	match set {
  	Some(SetOpenCommand::Bool(open)) => {
  	if open {
  	match self.anchor {
  	PopupAnchor::PointerFixed => {
  	self.ctx.memory_mut(|mem| mem.open_popup_at(id, hover_pos));
  	}
  	_ => Popup::open_id(&self.ctx, id),
  	}
  	} else {
  	Self::close_id(&self.ctx, id);
  	}
  	}
  	Some(SetOpenCommand::Toggle) => {
  	Self::toggle_id(&self.ctx, id);
  	}
  	None => {
  	self.ctx.memory_mut(|mem| mem.keep_popup_open(id));
  	}
  	}
  	}
  	if !self.open_kind.is_open(self.id, &self.ctx) {
  	return None;
  	}
  	let best_align = self.get_best_align();
  	let Popup {
  	id,
  	ctx,
  	anchor,
  	open_kind,
  	close_behavior,
  	kind,
  	info,
  	layer_id,
  	rect_align: _,
  	alternative_aligns: _,
  	gap,
  	widget_clicked_elsewhere,
  	width,
  	sense,
  	layout,
  	frame,
  	style,
  	} = self;
  	if kind != PopupKind::Tooltip {
  	ctx.pass_state_mut(|fs| {
  	fs.layers
  	.entry(layer_id)
  	.or_default()
  	.open_popups
  	.insert(id)
  	});
  	}
  	let anchor_rect = anchor.rect(id, &ctx)?;
  	let (pivot, anchor) = best_align.pivot_pos(&anchor_rect, gap);
  	let mut area = Area::new(id)
  	.order(kind.order())
  	.pivot(pivot)
  	.fixed_pos(anchor)
  	.sense(sense)
  	.layout(layout)
  	.info(info.unwrap_or_else(|| {
  	UiStackInfo::new(kind.into()).with_tag_value(
  	MenuConfig::MENU_CONFIG_TAG,
  	MenuConfig::new()
  	.close_behavior(close_behavior)
  	.style(style.clone()),
  	)
  	}));
  	if let Some(width) = width {
  	area = area.default_width(width);
  	}
  	let mut response = area.show(&ctx, |ui| {
  	style.apply(ui.style_mut());
  	let frame = frame.unwrap_or_else(|| Frame::popup(ui.style()));
  	frame.show(ui, content).inner
  	});
  	let closed_by_click = match close_behavior {
  	PopupCloseBehavior::CloseOnClick => widget_clicked_elsewhere,
  	PopupCloseBehavior::CloseOnClickOutside => {
  	widget_clicked_elsewhere && response.response.clicked_elsewhere()
  	}
  	PopupCloseBehavior::IgnoreClicks => false,
  	};
  	// If a submenu is open, the CloseBehavior is handled there
  	let is_any_submenu_open = !MenuState::is_deepest_sub_menu(&response.response.ctx, id);
  	let should_close = (!is_any_submenu_open && closed_by_click)
  	|| ctx.input(|i| i.key_pressed(Key::Escape))
  	|| response.response.should_close();
  	if should_close {
  	response.response.set_close();
  	}
  	match open_kind {
  	OpenKind::Open | OpenKind::Closed => {}
  	OpenKind::Bool(open) => {
  	if should_close {
  	*open = false;
  	}
  	}
  	OpenKind::Memory { .. } => {
  	if should_close {
  	ctx.memory_mut(|mem| mem.close_popup(id));
  	}
  	}
  	}
  	Some(response)
  	}
  	}

[Omustardo]

I've summarized things into an issue: #7390

I'm closing this so we can track it in one place.