An interactive tip “wobbles” when in a fixed position.

The tip’s contour is based on the contents' actual bounding box width. When using it interactively with a pointer, the contents’ width tends to change all the time, by a few pixels.

When the tip’s position follows the mouse, this is not a problem, but when it is fixed, it makes the tip’s left and right sides “wobble”, which is distracting.

The following ideas didn't work:

• when the tip’s width shrinks by a small amount, we keep the older width. Alas, this would require to add state to keep track of the width.
• we introduce a minWidth option to the tip mark (#1573). Alas, it creates a bit of confusion with the lineWidth (text clipping) option, which is in approximate ems, and would require the user to do awkward conversions.

We could try to make numbers and dates use fontVariant: tabular-nums, to alleviate this at least a little?

Start by locating the interactive tip mark and the code that derives its contour from the contents’ bounding box. Reproduce the behavior with a fixed-position tip and changing numeric or date content; done means the tip’s left and right sides remain stable without introducing the rejected minWidth or state-based approaches.