## ADDED Requirements

### Requirement: Per-tile grid toggle
Each viewport tile SHALL have an independent grid visibility setting. Toggling the grid in one tile SHALL NOT affect other tiles.

#### Scenario: Grid on in Tile A, off in Tile B
- **WHEN** the user toggles grid ON in tile A and OFF in tile B
- **THEN** tile A shows the ground grid and tile B does not

### Requirement: Per-tile anti-aliasing toggle
Each viewport tile SHALL have an independent line-AA setting. Toggling AA in one tile SHALL NOT affect other tiles.

#### Scenario: AA on in Tile A, off in Tile B
- **WHEN** the user toggles AA ON in tile A and OFF in tile B
- **THEN** tile A renders line overlays with GL_LINE_SMOOTH, tile B renders without

### Requirement: Per-tile background color
Each viewport tile SHALL have an independent background color. Changing the background color in one tile SHALL NOT affect other tiles.

#### Scenario: Two tiles show different background colors
- **WHEN** the user sets tile A's background to "Black" and tile B's background to "Dark Gray"
- **THEN** tile A renders with a black background and tile B with a dark gray background

### Requirement: Per-tile bounding box display
Each viewport tile SHALL have an independent bounding box display mode (None / Per Object / All Selection). Changing the bbox mode in one tile SHALL NOT affect other tiles.

#### Scenario: BBox mode differs between tiles
- **WHEN** the user sets tile A to "Per Object" bbox mode and tile B to "None"
- **THEN** tile A draws bounding boxes on each selected prim, tile B draws none

### Requirement: Per-tile render delegate
Each viewport tile SHALL support an independent render delegate selection. Changing the render delegate in one tile SHALL NOT affect other tiles.

#### Scenario: Storm in Tile A, HdEmbree in Tile B
- **WHEN** the user selects "HdStorm" for tile A and "HdEmbree" for tile B
- **THEN** tile A renders via HdStorm and tile B via HdEmbree

### Requirement: Compact per-tile toolbar
Each tile's toolbar SHALL use compact icon-only buttons (16×16) arranged in a single horizontal row above the rendered image, consuming no more than 32px height. Tooltips SHALL be available on hover.

#### Scenario: Toolbar renders compactly in a small tile
- **WHEN** a tile is 300px wide in an HSplit layout
- **THEN** the toolbar fits within the tile width without clipping, using a horizontal scroll or overflow dropdown if necessary