In order to implement the Industry Standard keymap and other similar left-click keymaps, we'll need to move several distinct operations to the left mouse button.
For example, in the Dopesheet/Timeline, we'd need the ability to distinguish if the user clicks in an empty area (deselect), drags on the playhead (moves playhead) or drags in an empty area (box select) or drags on a selected item (move).
Currently in Blender, these are all different actions that are explicitly executed via different shortcuts, but we'd need a way to make this distinction in the keymap somehow.
Below are all the specific examples:
=Dopesheet, Graph Editor, Timeline, NLA
//Item = keys in Dopesheet+Timeline, handles in Graph Editor, Strips in NLA//
- Dragging near Playhead moves playhead
- Dragging in empty area creates Box select
- Clicking on item selects item
- Clicking on empty area deselects all
- Dragging item moves item
- If no item is selected, dragging node moves that one item
=Node Editors
- Dragging in empty area creates Box select
- Clicking on item selects node
- Clicking on empty area deselects all
- Dragging item moves selected nodes
- If no node is selected, dragging node moves that one node