Mouse button

This

Does this...

Left

Click in workspace or click an element

Places and snaps to points in the workspace.

CTRL + click

Places points in exact alignment with existing points (linear snap).

SHIFT + click

After having placed the first point, you can create additional points so that they are orthogonal (provided Enter at right angles or Enter using cursor snap is not active in the dialog line).

Middle

Double-click

Sets the display scale so that all the visible elements are displayed in their entirety.

Click and drag

Pans in the current viewport.

SHIFT + click and drag

Pans in the current viewport.

CTRL + click and drag

Zooms in.

ALT + click and drag

Zooms dynamically (cursor = center). When you move the cursor up, the system zooms in and when you move it down, the system zooms out.

Right

Click in workspace

Opens the shortcut menu for entering points.

Confirms the entry when requested in the dialog line: <confirm>.

Click a toolbar

Quits a tool (= ESC key).