Viewport interactions should only work when the mouse is over the viewport.

[muhuk]

Currently viewport renders to the entire window, and egui is overdrawn on top of it. So keyboard & mouse interactions happens as long as the window (app) is active.

Possible solutions:

• Render onto egui's central panel. This makes the UI architecture a bit questionable.
• Use bevy UI for the side panels and render onto something in the central UI element. This messes up spacing around the menu a bit, it will still be overdrawn.
• Detect when the mouse is actually over the viewport area visible.

[muhuk]

Render onto egui's central panel. This makes the UI architecture a bit questionable.

This example illustrates how a camera can be targeted to render onto an image.

[muhuk]

Using bevy UI and setting FocusPolicy::Block does not product desired effect. Viewport interation still works when the mouse is over the UI node.

Instead of the 2 methods mentioned above, detection of the UI section mouse is over is necessary.