Canvas

The design surface: navigation, selection, transform, snapping and ordering.

Clicking, marquee and the selection chrome.

GestureResult
Click a componentSelects it.
Shift / Ctrl / Cmd + clickAdds to or removes from the selection.
Drag on empty canvasMarquee-selects everything the rectangle touches.
Drag a marquee to the viewport edgeAuto-scrolls while you keep dragging.
Click empty canvasClears the selection.
Right-click a componentSelects it (a right click inside the selection keeps the selection) and opens its context menu.
Right-click empty canvasClears the selection and opens the canvas menu: Paste, Select All, zoom.
Alt / Option + click, one item selectedClips that item into the item under the pointer, moving it directly in front. Alt-click the same base again to release. The two items have to share a group.
Click a part a mask or clip hidesPasses through to whatever is visible there.

A small drag threshold keeps an accidental two-pixel wobble from starting a marquee. The selection's actions live in the right-click context menu.

A multi-selection with its context menu open.
A multi-selection with its context menu open.