Make selection smarter in Blender 2.8

This is something that affects just those using the new left select keymap, with right click select the separation between selection and action is very clear so there's no issue there and that shouldn't change. But I think is perfectly possible to have the LMB to both select and perform actions, is just a matter of making the selection smarter (I hope that's not too difficult technically).

I'm assuming here that people coming to Blender for the first time will be using mostly the toolbar and don't know (or use at all) the tool's shortcuts.

• First, box selection should be part of the simple selection tool, and not a separate tool doing only one thing, which doesn't make much sense.
• Second, simple selection and box selection (object, and edit mode) should be possible regardless of the tool active at the moment without having to change the active tool.
• Third, the move, rotate and scale widgets should be overlays instead of tools, to be able to use them even if another tool is active. This would be very handy for example if I'm extruding faces on a model and I want to do simple transforms on each face without changing tools everytime, because it becomes very slow.

The basic functionality of selection+box selection combined could be something like this: (I think the important part is to detect if something is selected or not)

Object/Edit mode (Selection tool active):

• If nothing selected, click + drag on empty space will activate Box select.
• If one or more objects/components are selected, then click + drag on empty space will perform the tweak action, or grab (I don’t know how it’s called now).
• If one or more objects/components are selected, click+drag on one object/component will override the selection and perform the grab/tweak action only on the object/component clicked directly.
• If nothing is selected, click + drag on a object/component will select it and grab/tweak.
• Single click on empty space will deselect whatever is selected.
• Single click on an object/component selects it. (If other objects/components were selected before will be deselected).
• Shift+click adds to the current selection.
• Shift+click+drag activates box selection and adds to the current selection.
• Ctrl+click removes from the current selection.
• Ctrl+click+drag activates box selection and removes from the current selection.

Note that these things can already be done changing between simple select or box select depending on the need, just not as part of one single tool, my proposal is to merge them both to have a faster workflow.

Now, with other tools active (extrude, inset, bevel, etc) simple click select and box select should be activated ONLY IF NOTHING IS SELECTED, otherwise the tool action will always have priority:

• If nothing selected, click + drag on empty space will activate Box select.
• If one or more objects/components are selected, then click + drag on empty space will perform the tool's action.
• If nothing is selected, click + drag directly on a object/component will select it and perform the tool's action.
• Deselect should be done with AA or Alt+A

The "extrude to cursor" is a good example of this, when the tool is active there's no way to select new components without changing tools first; with the proposed method it would be possible to do the selection without leaving the extrude tool, Blender just needs to know when something is selected or not and perform selection or action accordingly.