Tab bar flickers to a large size momentarily when hitting "enter" with zsh

Environment

Windows 10.0.18362.0

Steps to reproduce

1. Launch WSL zsh shell
2. Hit enter

Expected behavior

Tab size remains consistent

Actual behavior

Tab size flickers in response to input in shell.

In other shells, the tab resizes frequently in response to a change in the title text to adapt to the size of it. It seems like zsh has some way to detect a maximum size and truncates it, but not before WSL has rendered the update.

Even in other shells that don't flicker, the "adaptive" behavior seems very strange; e.g. when I change directories it resizes the tab, causing frequent visual distraction as the UX is reorganized each time the shell title changes.

I am not sure if this behavior is intentional, but I think having a fixed, consistent tab size is a much better user experience then trying to adapt to the title as it changes. For example the way Chrome works is pretty sensible; use a larger size until there are too many tabs then shrink them all, but each tab should probably always be the same size -- or at least not change while someone's actively using the shell, as would be common when someone has a title that reflects the current directory which changes often.

Start by reproducing the flicker in a WSL zsh shell on Windows 10, then trace the tab-sizing update triggered by shell input and title changes. Done means the tab no longer momentarily grows when pressing Enter and its size remains consistent while the shell title changes.