High priority

Workflow:

• the plus button should use the new "Add SV/Container" modal instead of the old one (it's ok to "loose" the heuristics suggestions for now): Use the new modal with the blueprint panel "+" button #4652
• support right clicking on items to display a context menu with actions: Add contextual menu to blueprint tree for common actions #4823

Selection improvements

• make multi-selection compatible with future drag-and-drop and selection panel: Enforce homogenous multi-selections #4887
• introduced "parent selected" state for item that are contained in a parent which is selected: Highlight items related to the selected items #5257
• Support range multi-selection with shift modifier #4917
• select container when clicking in blank space: Clicking empty space where there is no view should select the container #4774

Drag and drop improvement:

• reorder with drag and drop:
  • Interactive layout items in blueprint tree view #2652
  • Add support for drag-and-drop in blueprint tree #4910
• Properly deal with the root container: Present the root container as the top-level viewport container and differentiate it from other container #4909
•  support multi-selection drag-and-drop: Drag-and-drop: add support for view hierarchy item multi-selection drag-and-drop #5307
•  Improve behaviour for grid container: because of how Grid container work (they support "holes", and tend to swap instead of reflow items when reordering), some drag operation have additional order side effects within the destination (grid) container.

Live-previews:

•  application layer discussion: Add support for previewing blueprint changes in response of user actions #4928
• Display a placeholder item to indicate the destination when the "Add SV/Container" modal is open #4958
• Live preview the effect of a blueprint tree drag-and-drop in progress in the viewport #4916
• preview blueprint layout while dragging tiles in the viewport: Preview blueprint changes when dragging views  #3164

Kitchen sink

Design improvement

The end goal is to make the blueprint tree UI contribute positively to the on-boarding experience. Ideally, tt should teach about "stuff", not require prior knowledge to be understood.

• subdue the label of the container to make it more distinct (not the icon, unless the container is hidden): Subdue container labels to distinguish them from space views #4855
• improve the visual distinction between containers, space views, data group and data item
  • Related: Update Space View/Container/Visualizer icons to represent both type and sub-type #4321
• A small circle is used as icon for components in the Stream Tree ui. From afar, this looks awfully close to the diamond used for entities, which is confusing.
• Consistent way to add/remove views and data to the blueprint in the UI #2697
• Make blueprint tree more scannable, and the concepts clearer by distinguishing containers, space views, and entities. #4743 (de-prioritised until a suitable design is available)
• Use entity/component icons homogeneously in the blueprint tree and the streams UIs #4964

Behaviour improvements

• support drag and drop for data as well
• When an entity is hovered elsewhere in the UI (selection panel, streams, etc.), the visual feedback is currently to hover the corresponding item(s) in the blueprint tree UI, which is visually very strong. A more toned-done approach might be better.
• Entities logged to the "/" don't show up in the blueprint hierarchy #2909
• containers look inactive although they are active
• hidden elements look inactive although they are active
• allow unhiding a single child from a hidden (direct or indirect) parent: Improve show/hide behaviour in the Blueprint Tree UI #3194
• hiding a container doesn't dim its children
• synchronise hover highlighting between blueprint tree UI and corresponding space view tabs: Highlight SpaceView tab when corresponding SpaceView is hovered elsewhere (e.g. in blueprint tree UI) #1129
• allow slow click: Allow slow clicks in the UI #2859
• allow selection on click down: Make blueprint selection immediate on mouse down #2858

Sister issue on Stream Tree UI:

• Streams Panel UI improvements #3150