Cannot interact when multiple gizmos are present on screen

[setzer22]

I tried adding multiple gizmos at the same time, and it seems only one of them (the first one I draw) is interactable.

I've tracked down the issue to lib.rs:158

        if let Some(pointer_ray) = self.pointer_ray(ui) {
            let interaction = ui.interact(self.config.viewport, self.id, Sense::click_and_drag()); // <- Here
            let dragging = interaction.dragged_by(PointerButton::Primary);

The problem is that egui will only generate drag events for one widget, so if you call ui.interact() during a frame where a drag starts, and the mouse is inside the interact area, no other call to interact will return a drag_started event no matter what.

I implemented a fix for this (PR incoming) which seems to be working fine. The trick is deferring the call to interact until we're sure that the mouse is hovering something we're interested in. 😄