Command palette icon potentially confusing

[isabela-pf]

The palette icon for the command palette in the sidebar could be confused for a rich text formatting menu. In early usability tests, 17 out 17 participants said that the palette icon must be for color formatting of some kind. Since rich text formatting can include color formatting, users may go to the palette icon expecting a text formatting menu and be confused.

Thoughts on this in relation to JupyterLab as a whole can be found at jupyterlab issue #5269. Currently, I am leaning towards a menu icon or something similar since I agree that the abstraction of a "command" is a challenge to effectively portray in an icon.

[isabela-pf]

After reviewing potential Material Icons, @tgeorgeux and @javag97 have convinced me that we need to make a new icon in order to properly communicate what the command palette is designed to do in its current state. I will be looking in to this and posting updates here as I work.

[isabela-pf]

We've narrowed it down to two similar icon designs.

The first combines the searching aspect of navigating the command palette with the standard icon for a command. As such, it describes the command part of command palette in a familiar way while tying it to the action users are encouraged to take via the command palette. However, it falls into the same patterns as described by this comment on PR #5920 in that it primarily describes code, which is not an accurate representation of the command palette.

The second option continues the emphasis on searching, but changes how the content of the command palette is represented. It now mimics Material Icons' existing icon for a list, which is both more close to what the command palette actually contains (a list of all commands/actions) and representative of what users see when using the command palette. This choice was made in response to the comment linked above and it intended to reflect the "set of things" description of the command palette. Its weaknesses are that its accuracy in representing the command palette as a list is too vague to be interpreted specifically and relies on a specific understanding of what the command palette is/does that may not be standard.