[Linking: microsoft/microsoft-ui-xaml#2711]

Environment

Windows build number: Microsoft Windows [Version 10.0.19041.329]
Windows Terminal version (if applicable): 1.1.1671.0 (Preview)

Steps to reproduce

• Grab the new Windows Terminal Preview off the MS Store.
• Given a config like this:

  "alwaysShowTabs": false, // true also replicates the issue
  "showTabsInTitlebar": false, // true also replicates the issue
  "tabWidthMode": "compact",

• Launch Terminal Preview
• No tabs are visible
• Control-Shift-T to open a new tab
• (!) Two tabs are visible, their titles are visible, ala "tabWidthMode": "titleLength"
• Control Tab back and forth, the titles remain visible
• Open the config file, and save it without changes. (Ctrl-, Ctrl-s, or Ctrl-, :wq as you prefer)
• Active tab unchanged, the other tab is now compacted down to its icon.
• Control Tab back and forth, only the active tab shows its title.

... And now it gets weird

• Open a new tab
• Three tabs are visible, the third one is active and shows its title, the other two compacted.
• Switch tabs with Control-Tab
• (!) The third tab's title remains visible, the active tab's title is also now visible.

• Switch back to the third tab with Shift-Control-Tab
• Third (active) tab's title is visible, the other tabs are now compacted.
• Switch back with to the first tab with Control-Tab
• Open the config file, and save it without changes.
• Active tab unchanged, the other tab is now compacted down to its icon.

Expected behavior

"compact" mode applies to tabs created since the config file was last saved.

Actual behavior

"compact" mode applies only to tabs open when the config file was last saved.

This took a while to test. I kept launch Windows Terminal by muscle memory. -_-