From 2d9fe2bec1a51222f56ccb32dbc516ecc74eb061 Mon Sep 17 00:00:00 2001
From: Siraaj Khandkar <siraaj@khandkar.net>
Date: Sat, 29 Feb 2020 21:47:47 -0500
Subject: [PATCH] Note solution to Thunderbird UI scaling problem

---
 notes-thunderbird.md | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/notes-thunderbird.md b/notes-thunderbird.md
index 12044d3..ca67872 100644
--- a/notes-thunderbird.md
+++ b/notes-thunderbird.md
@@ -16,4 +16,29 @@ and select the desired profile, after which normal starts will use it:
 
 I copied a profile from 4k resolution computer to a 2k one, now icons and text
 are huge. How to scale it back down? Don't see anything relevant-looking in the
-settings...
+settings; I looked for "scale", "zoom" and "size".
+
+### Solution
+
+In config editor, find property:
+
+    layout.css.devPixelsPerPx
+
+then change its value from 2.0 to 1.0.
+
+#### Source
+
+Make a fresh profile and examine `prefs.js` diff until something looks promising.
+
+    $ thunderbird  # Looks bad. Close it.
+    $ mv ~/.thunderbird ~/.thunderbird.bak
+    $ thunderbird  # Close it. Now we have a fresh profile.
+    $ vimdiff ~/.thunderbird/newxxx.default/prefs.js ~/.thunderbird.bak/oldxxx.default/prefs.js
+        # Examine every difference until something looks promising. Value 2.0
+        # looks like a zoom value and it is refering to some pixel-to-pixel
+        # ratio - looks promising!
+    $ rm -rf ~/.thunderbird
+    $ mv ~/.thunderbird.bak ~/.thunderbird
+    $ thunderbird
+        # Open config editor, look for devPixelsPerPx and change to 1.0.
+        # Looks good!
-- 
2.20.1