Fonts for [NSWebView preferences] are shared across group and regular chats

[earthmkii]

If I set Regular Chats and Group Chats to the same message style, all options may be unique, but font size is shared.

To reproduce:

1. Set both Group and Regular Chat message styles to the same style. Variants may be different—it doesn't matter.
2. Set the Text Display setting for both chats to something unique (ex: Helvetica 10 and Times 36).
3. Open both a group chat and regular chat window.
4. In the Messages pref pane, watch and enjoy the font styles for both windows toggle as you switch between the Group and Regular tabs.

[jas8522]

Yes indeed.

[zacw]

The way the fonts are set, this is done intentionally (more or less) because the fonts were intended to update to all windows as it was happening.

One way might be to share the preference instances between group chats and regular chats separately, by setting the preference identifier.

[Evan Schoenberg]

(In  9232899b7ef5) For our WebViews, use a preferences identifier of activeStyle-preferenceGroup. This uniques group chats from one-on-one chats when their preferences are being stored separately. The WebView preference identifier is used only transiently in our usage to allow all WebViews to update when one changes (via the preferences); this doesn't change our actual storage and retrieval of the prefs. Fixes #12810 by implementing Zac's suggestion there.