Why the tools work the way they do¶

The plot follows three rules:

1. Navigating never selects, and selecting never navigates. Moving through time is something you do all the time; a selection is something you build up and keep.
2. The default tool cannot change the selection by accident. With Pan, a plain click does nothing, because a click often only gives the plot focus, or is a short drag that didn't move. Selecting a single event with Pan takes a deliberate Shift-click.
3. The active tool shows: a pressed button, the cursor, and a hint beside the counts ("Drag: pan · Shift-drag: zoom to a range").

Zoom is in time only¶

A timeline's two axes are not alike: time is continuous and zoomable, lanes are rows. So a zoom box is a band over all lanes, with the length of the range it shows, and the wheel zooms time. Lanes scroll instead.

No lasso¶

Lanes are rows, so a box of time × lanes covers what a lasso would on a scatter plot. One tool fewer to learn.

The time axis is a handle¶

Dragging on the time axis zooms to that range in any tool, and with Select selects that range over all lanes. Trace viewers use the axis the same way; it is the quickest way to zoom exactly.

The wheel waits for a click¶

In a notebook the wheel scrolls the page. A plot that zoomed on every scroll would catch the page's scrolling, so the wheel zooms only after a click into the plot, in full screen, or with Ctrl or ⌘ held.