Shape drawing tools: allow click-and-release in place to add first vertex

Problem

You have a fill material selected and you want to create a filled shape with the polyline tool (because the fill tool is failing to fill your art properly :)).

Attempting to click-and-release to create the first vertex does nothing.

So you click and drag, but have no indication that anything is happening; the start point isn't indicated, and because a filled polygon with only two vertices has no width, no shape preview shows up. To create the shape you have to stop dragging, then click-and-release again at the location of each corner you want to add.

So you must first click-drag-release to place the first corner, and after that click-and-release for subsequent corners. This is an incoherent user experience.

Proposal

All of the green shape drawing tools, including the polyline tool, allow an initial click-and-release in place to place the first vertex/control point. Subsequent clicking adds points and control handles can be dragged where appropriate. Pressing return completes and renders the shape.