diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index f3c45f12d..dd222b53a 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -69,6 +69,9 @@ Improved terminal support
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 - Support for curly underlines in `fish_color_*` variables and :doc:`set_color <cmds/set_color>` (:issue:`10957`).
 - Underlines can now be colored independent of text (:issue:`7619`).
+- Errors are now highlighted with curly underlines in the default themes.
+  For compatibility with terminals that interpret the curly-underline escape sequence in an unexpected way,
+  the default themes enable this only if the terminal advertises support for the ``Su`` capability via XTGETTCAP.
 - New documentation page `Terminal Compatibility <terminal-compatibility.html>`_ (also accessible via ``man fish-terminal-compatibility``) lists required and optional terminal control sequences used by fish.
 - :doc:`status <cmds/status>` learned the ``xtgettcap`` subcommand, to query terminfo capabilities via XTGETTCAP commands.
 - :doc:`status <cmds/status>` learned the ``xtversion`` subcommand, to show the terminal's name and version (as reported by via the XTVERSION command).
diff --git a/share/functions/__fish_config_interactive.fish b/share/functions/__fish_config_interactive.fish
index 4874831df..7d81a1f28 100644
--- a/share/functions/__fish_config_interactive.fish
+++ b/share/functions/__fish_config_interactive.fish
@@ -30,7 +30,7 @@ if status is-interactive
     # Commands to run in interactive sessions can go here
 end" >$__fish_config_dir/config.fish
 
-        echo yes | fish_config theme save "fish default" --track
+        fish_config theme save "fish default" --yes --track
         set -Ue fish_color_keyword fish_color_option
     end
     if test $__fish_initialized -lt 3800 && test "$fish_color_search_match[1]" = bryellow
diff --git a/share/functions/__fish_in_gnu_screen.fish b/share/functions/__fish_in_gnu_screen.fish
new file mode 100644
index 000000000..a95664889
--- /dev/null
+++ b/share/functions/__fish_in_gnu_screen.fish
@@ -0,0 +1,3 @@
+function __fish_in_gnu_screen
+    test -n "$STY" || contains -- $TERM screen screen-256color
+end
diff --git a/share/functions/__fish_in_terminal_multiplexer.fish b/share/functions/__fish_in_terminal_multiplexer.fish
new file mode 100644
index 000000000..22b3cc363
--- /dev/null
+++ b/share/functions/__fish_in_terminal_multiplexer.fish
@@ -0,0 +1,9 @@
+function __fish_in_terminal_multiplexer
+    set -l terminal_name "(status xtversion | string match -r '^\S*')"
+    string match -q -- tmux $terminal_name ||
+        __fish_in_gnu_screen ||
+        # Emacs does probably not support multiplexing between multiple parent
+        # terminals, but it is affected by the same issues.  Same for Vim's
+        # :terminal TODO detect that before they implement XTGETTCAP.
+        contains -- $TERM dvtm-256color eterm eterm-color
+end
diff --git a/share/functions/__fish_shared_key_bindings.fish b/share/functions/__fish_shared_key_bindings.fish
index 19e624f4c..3eef69f03 100644
--- a/share/functions/__fish_shared_key_bindings.fish
+++ b/share/functions/__fish_shared_key_bindings.fish
@@ -78,9 +78,7 @@ function __fish_shared_key_bindings -d "Bindings shared between emacs and vi mod
     bind --preset $argv alt-o __fish_preview_current_file
     bind --preset $argv alt-w __fish_whatis_current_token
     bind --preset $argv ctrl-l (
-        if test -z "$STY"
-            and not string match -qr -- '^(screen|screen-256color)$' $TERM
-            and __fish_xtgettcap indn
+        if not __fish_in_gnu_screen && and __fish_xtgettcap indn
             echo scrollback-push
         end
     ) clear-screen
diff --git a/share/functions/fish_config.fish b/share/functions/fish_config.fish
index 743e69577..997907927 100644
--- a/share/functions/fish_config.fish
+++ b/share/functions/fish_config.fish
@@ -5,7 +5,7 @@ function fish_config --description "Launch fish's web based configuration" \
     --inherit-variable theme_var_filter
 
     set -l _flag_track
-    argparse h/help track -- $argv
+    argparse h/help track yes -- $argv
     or return
 
     if set -q _flag_help
@@ -20,6 +20,10 @@ function fish_config --description "Launch fish's web based configuration" \
         echo >&2 fish_config: --track: unknown option
         return 1
     end
+    if set -q _flag_yes[1] && not { contains "$cmd" prompt theme && test "$argv[1]" = save }
+        echo >&2 fish_config: --yes: unknown option
+        return 1
+    end
 
     set -q cmd[1]
     or set cmd browse
@@ -152,8 +156,8 @@ function fish_config --description "Launch fish's web based configuration" \
                         functions --erase fish_right_prompt
                     end
                 case save
-                    read -P"Overwrite prompt? [y/N]" -l yesno
-                    if string match -riq 'y(es)?' -- $yesno
+                    if set -q _flag_yes[1] ||
+                            { read -P"Overwrite prompt? [y/N]" -l yesno; string match -riq 'y(es)?' -- $yesno }
                         echo Overwriting
                         # Skip the cp if unnecessary,
                         # or we'd throw an error on a stock fish.
@@ -282,8 +286,10 @@ function fish_config --description "Launch fish's web based configuration" \
                     set -l have_colors
 
                     if contains -- $cmd save
-                        read -P"Overwrite your current theme? [y/N] " -l yesno
-                        if not string match -riq 'y(es)?' -- $yesno
+                        if not set -q _flag_yes &&
+                                { read -P"Overwrite your current theme? [y/N] " -l yesno
+                                    not string match -riq 'y(es)?' -- $yesno
+                                }
                             echo Not overwriting >&2
                             return 1
                         end
@@ -362,10 +368,14 @@ function __fish_config_theme_get
     set -l dirs $__fish_config_dir/themes $__fish_data_dir/tools/web_config/themes
     set -l files $dirs/$argv[1].theme
     set -l file
+    set -l is_default_theme false
 
     for f in $files
         if test -e "$f"
             set file $f
+            if test $f = $__fish_data_dir/tools/web_config/themes/$argv[1].theme
+                set is_default_theme true
+            end
             break
         end
     end
@@ -373,6 +383,7 @@ function __fish_config_theme_get
     if not set -q file[1]
         if status list-files tools/web_config/themes/$argv[1].theme &>/dev/null
             set file tools/web_config/themes/$argv[1].theme
+            set is_default_theme true
         else
             echo "No such theme: $argv[1]" >&2
             echo "Searched directories: $dirs" >&2
@@ -380,11 +391,18 @@ function __fish_config_theme_get
         end
     end
 
-    if string match -qr '^tools/' -- $file
-        status get-file $file
-    else
-        string join \n <$file
+    set -l content (
+        if string match -qr '^tools/' -- $file
+            status get-file $file
+        else
+            string join \n <$file
+        end
+    )
+    if $is_default_theme && not __fish_in_gnu_screen && not __fish_xtgettcap Su && not __fish_in_terminal_multiplexer
+        set content (string replace -- --underline=curly "" $content)
     end
+
+    string join \n $content
 end
 
 function __fish_config_show_tracked_color_vars
diff --git a/share/tools/web_config/themes/Base16 Default Dark.theme b/share/tools/web_config/themes/Base16 Default Dark.theme
index fe95277c7..7f42441a5 100644
--- a/share/tools/web_config/themes/Base16 Default Dark.theme	
+++ b/share/tools/web_config/themes/Base16 Default Dark.theme	
@@ -10,7 +10,7 @@ fish_color_comment f7ca88
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end ba8baf
-fish_color_error ab4642
+fish_color_error ab4642 --underline=curly
 fish_color_escape 86c1b9
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Base16 Default Light.theme b/share/tools/web_config/themes/Base16 Default Light.theme
index 842a051d1..7fc54435f 100644
--- a/share/tools/web_config/themes/Base16 Default Light.theme	
+++ b/share/tools/web_config/themes/Base16 Default Light.theme	
@@ -10,7 +10,7 @@ fish_color_comment f7ca88
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end ba8baf
-fish_color_error ab4642
+fish_color_error ab4642 --underline=curly
 fish_color_escape 86c1b9
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Base16 Eighties.theme b/share/tools/web_config/themes/Base16 Eighties.theme
index d2f06d96e..4bd93d251 100644
--- a/share/tools/web_config/themes/Base16 Eighties.theme	
+++ b/share/tools/web_config/themes/Base16 Eighties.theme	
@@ -10,7 +10,7 @@ fish_color_comment ffcc66
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end cc99cc
-fish_color_error f2777a
+fish_color_error f2777a --underline=curly
 fish_color_escape 66cccc
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Bay Cruise.theme b/share/tools/web_config/themes/Bay Cruise.theme
index c07f35a77..f6fd7799f 100644
--- a/share/tools/web_config/themes/Bay Cruise.theme	
+++ b/share/tools/web_config/themes/Bay Cruise.theme	
@@ -9,7 +9,7 @@ fish_color_comment FF9640
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end FFB273
-fish_color_error FF7400
+fish_color_error FF7400 --underline=curly
 fish_color_escape 00a6b2
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Dracula.theme b/share/tools/web_config/themes/Dracula.theme
index ca943f1e4..e49ad699d 100644
--- a/share/tools/web_config/themes/Dracula.theme
+++ b/share/tools/web_config/themes/Dracula.theme
@@ -21,7 +21,7 @@ fish_color_comment 6272a4
 fish_color_cwd 50fa7b
 fish_color_cwd_root red
 fish_color_end ffb86c
-fish_color_error ff5555
+fish_color_error ff5555 --underline=curly
 fish_color_escape ff79c6
 fish_color_history_current --bold
 fish_color_host bd93f9
diff --git a/share/tools/web_config/themes/Fairground.theme b/share/tools/web_config/themes/Fairground.theme
index cb62017ad..02b1ac7db 100644
--- a/share/tools/web_config/themes/Fairground.theme
+++ b/share/tools/web_config/themes/Fairground.theme
@@ -9,7 +9,7 @@ fish_color_comment FFE100
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end 8D003B
-fish_color_error EC3B86
+fish_color_error EC3B86 --underline=curly
 fish_color_escape 00a6b2
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Just a Touch.theme b/share/tools/web_config/themes/Just a Touch.theme
index 07f3f5e17..865a98a67 100644
--- a/share/tools/web_config/themes/Just a Touch.theme	
+++ b/share/tools/web_config/themes/Just a Touch.theme	
@@ -9,7 +9,7 @@ fish_color_comment B0B0B0
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end 969696
-fish_color_error FFA779
+fish_color_error FFA779 --underline=curly
 fish_color_escape 00a6b2
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Lava.theme b/share/tools/web_config/themes/Lava.theme
index b52743aad..38a115107 100644
--- a/share/tools/web_config/themes/Lava.theme
+++ b/share/tools/web_config/themes/Lava.theme
@@ -6,7 +6,7 @@ fish_color_command FF9400
 fish_color_quote BF9C30
 fish_color_redirection BF5B30
 fish_color_end FF4C00
-fish_color_error FFDD73
+fish_color_error FFDD73 --underline=curly
 fish_color_param FFC000
 fish_color_comment A63100
 fish_color_selection white --background=brblack --bold
diff --git a/share/tools/web_config/themes/Mono Lace.theme b/share/tools/web_config/themes/Mono Lace.theme
index c53f38596..f9276568b 100644
--- a/share/tools/web_config/themes/Mono Lace.theme	
+++ b/share/tools/web_config/themes/Mono Lace.theme	
@@ -9,7 +9,7 @@ fish_color_comment 4e4e4e
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end 767676
-fish_color_error b2b2b2
+fish_color_error b2b2b2 --underline=curly
 fish_color_escape 00a6b2
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Mono Smoke.theme b/share/tools/web_config/themes/Mono Smoke.theme
index 4f7788556..ffd974b28 100644
--- a/share/tools/web_config/themes/Mono Smoke.theme	
+++ b/share/tools/web_config/themes/Mono Smoke.theme	
@@ -6,7 +6,7 @@ fish_color_command ffffff
 fish_color_quote a8a8a8
 fish_color_redirection 808080
 fish_color_end 949494
-fish_color_error 585858
+fish_color_error 585858 --underline=curly
 fish_color_param d7d7d7
 fish_color_comment bcbcbc
 fish_color_selection white --background=brblack --bold
diff --git a/share/tools/web_config/themes/None.theme b/share/tools/web_config/themes/None.theme
index d615ad3a5..947a47d6b 100644
--- a/share/tools/web_config/themes/None.theme
+++ b/share/tools/web_config/themes/None.theme
@@ -9,7 +9,7 @@ fish_color_comment
 fish_color_cwd normal
 fish_color_cwd_root normal
 fish_color_end
-fish_color_error
+fish_color_error --underline=curly
 fish_color_escape
 fish_color_history_current
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Nord.theme b/share/tools/web_config/themes/Nord.theme
index ff43c356e..cb9dd3ce0 100644
--- a/share/tools/web_config/themes/Nord.theme
+++ b/share/tools/web_config/themes/Nord.theme
@@ -11,7 +11,7 @@ fish_color_comment 4c566a --italics
 fish_color_cwd 5e81ac
 fish_color_cwd_root bf616a
 fish_color_end 81a1c1
-fish_color_error bf616a
+fish_color_error bf616a --underline=curly
 fish_color_escape ebcb8b
 fish_color_history_current e5e9f0 --bold
 fish_color_host a3be8c
diff --git a/share/tools/web_config/themes/Old School.theme b/share/tools/web_config/themes/Old School.theme
index 819dd7a9c..f7ba36201 100644
--- a/share/tools/web_config/themes/Old School.theme	
+++ b/share/tools/web_config/themes/Old School.theme	
@@ -9,7 +9,7 @@ fish_color_comment 30BE30
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end FF7B7B
-fish_color_error A40000
+fish_color_error A40000 --underline=curly
 fish_color_escape 00a6b2
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Seaweed.theme b/share/tools/web_config/themes/Seaweed.theme
index 3a84d72ab..bc9f4cac8 100644
--- a/share/tools/web_config/themes/Seaweed.theme
+++ b/share/tools/web_config/themes/Seaweed.theme
@@ -9,7 +9,7 @@ fish_color_comment 5C9900
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end 8EEB00
-fish_color_error 60B9CE
+fish_color_error 60B9CE --underline=curly
 fish_color_escape 00a6b2
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Snow Day.theme b/share/tools/web_config/themes/Snow Day.theme
index cf98b3144..e4912afa0 100644
--- a/share/tools/web_config/themes/Snow Day.theme	
+++ b/share/tools/web_config/themes/Snow Day.theme	
@@ -6,7 +6,7 @@ fish_color_command 164CC9
 fish_color_quote 4C3499
 fish_color_redirection 248E8E
 fish_color_end 02BDBD
-fish_color_error 9177E5
+fish_color_error 9177E5 --underline=curly
 fish_color_param 4319CC
 fish_color_comment 007B7B
 fish_color_selection white --background=brblack --bold
diff --git a/share/tools/web_config/themes/Solarized Dark.theme b/share/tools/web_config/themes/Solarized Dark.theme
index 84493d2d2..aaea5d14f 100644
--- a/share/tools/web_config/themes/Solarized Dark.theme	
+++ b/share/tools/web_config/themes/Solarized Dark.theme	
@@ -10,7 +10,7 @@ fish_color_comment 586e75
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end 268bd2
-fish_color_error dc322f
+fish_color_error dc322f --underline=curly
 fish_color_escape 00a6b2
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Solarized Light.theme b/share/tools/web_config/themes/Solarized Light.theme
index 6f1de058f..d11e5bd6c 100644
--- a/share/tools/web_config/themes/Solarized Light.theme	
+++ b/share/tools/web_config/themes/Solarized Light.theme	
@@ -7,7 +7,7 @@ fish_color_command 586e75
 fish_color_quote 839496
 fish_color_redirection 6c71c4
 fish_color_end 268bd2
-fish_color_error dc322f
+fish_color_error dc322f --underline=curly
 fish_color_param 657b83
 fish_color_comment 93a1a1
 fish_color_selection white --background=brblack --bold
diff --git a/share/tools/web_config/themes/Tomorrow Night Bright.theme b/share/tools/web_config/themes/Tomorrow Night Bright.theme
index 3dffc7daf..00dc49613 100644
--- a/share/tools/web_config/themes/Tomorrow Night Bright.theme	
+++ b/share/tools/web_config/themes/Tomorrow Night Bright.theme	
@@ -10,7 +10,7 @@ fish_color_comment e7c547
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end c397d8
-fish_color_error d54e53
+fish_color_error d54e53 --underline=curly
 fish_color_escape 00a6b2
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/Tomorrow Night.theme b/share/tools/web_config/themes/Tomorrow Night.theme
index 17d371622..06d82a800 100644
--- a/share/tools/web_config/themes/Tomorrow Night.theme	
+++ b/share/tools/web_config/themes/Tomorrow Night.theme	
@@ -7,7 +7,7 @@ fish_color_command b294bb
 fish_color_quote b5bd68
 fish_color_redirection 8abeb7
 fish_color_end b294bb
-fish_color_error cc6666
+fish_color_error cc6666 --underline=curly
 fish_color_param 81a2be
 fish_color_comment f0c674
 fish_color_selection white --background=brblack --bold
diff --git a/share/tools/web_config/themes/Tomorrow.theme b/share/tools/web_config/themes/Tomorrow.theme
index f84d95652..742e5f039 100644
--- a/share/tools/web_config/themes/Tomorrow.theme
+++ b/share/tools/web_config/themes/Tomorrow.theme
@@ -10,7 +10,7 @@ fish_color_comment eab700
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end 8959a8
-fish_color_error c82829
+fish_color_error c82829 --underline=curly
 fish_color_escape 00a6b2
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/ayu Dark.theme b/share/tools/web_config/themes/ayu Dark.theme
index 65737b1bb..175db47e7 100644
--- a/share/tools/web_config/themes/ayu Dark.theme	
+++ b/share/tools/web_config/themes/ayu Dark.theme	
@@ -7,7 +7,7 @@ fish_color_command 39BAE6
 fish_color_quote C2D94C
 fish_color_redirection FFEE99
 fish_color_end F29668
-fish_color_error FF3333
+fish_color_error FF3333 --underline=curly
 fish_color_param B3B1AD
 fish_color_comment 626A73
 fish_color_selection --background=E6B450 --bold
diff --git a/share/tools/web_config/themes/ayu Light.theme b/share/tools/web_config/themes/ayu Light.theme
index b2cfa2446..8fc78f624 100644
--- a/share/tools/web_config/themes/ayu Light.theme	
+++ b/share/tools/web_config/themes/ayu Light.theme	
@@ -10,7 +10,7 @@ fish_color_comment ABB0B6
 fish_color_cwd 399EE6
 fish_color_cwd_root red
 fish_color_end ED9366
-fish_color_error F51818
+fish_color_error F51818 --underline=curly
 fish_color_escape 4CBF99
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/ayu Mirage.theme b/share/tools/web_config/themes/ayu Mirage.theme
index 626b4a543..1b2029e79 100644
--- a/share/tools/web_config/themes/ayu Mirage.theme	
+++ b/share/tools/web_config/themes/ayu Mirage.theme	
@@ -10,7 +10,7 @@ fish_color_comment 5C6773
 fish_color_cwd 73D0FF
 fish_color_cwd_root red
 fish_color_end F29E74
-fish_color_error FF3333
+fish_color_error FF3333 --underline=curly
 fish_color_escape 95E6CB
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/share/tools/web_config/themes/coolbeans.theme b/share/tools/web_config/themes/coolbeans.theme
index 804722f6e..4c7cd18f5 100644
--- a/share/tools/web_config/themes/coolbeans.theme
+++ b/share/tools/web_config/themes/coolbeans.theme
@@ -9,7 +9,7 @@ fish_color_comment '888'  '--italics'
 fish_color_cwd 0A0
 fish_color_cwd_root A00
 fish_color_end 009900
-fish_color_error F22
+fish_color_error F22 --underline=curly
 fish_color_escape 0AA
 fish_color_history_current 0AA
 fish_color_host normal
diff --git a/share/tools/web_config/themes/fish default.theme b/share/tools/web_config/themes/fish default.theme
index 87f0759fc..b1e582e0e 100644
--- a/share/tools/web_config/themes/fish default.theme	
+++ b/share/tools/web_config/themes/fish default.theme	
@@ -11,7 +11,7 @@ fish_color_comment red
 fish_color_cwd green
 fish_color_cwd_root red
 fish_color_end green
-fish_color_error brred
+fish_color_error brred --underline=curly
 fish_color_escape brcyan
 fish_color_history_current --bold
 fish_color_host normal
diff --git a/tests/checks/fish_config.fish b/tests/checks/fish_config.fish
index 8e34abbbb..7c3daa0fa 100644
--- a/tests/checks/fish_config.fish
+++ b/tests/checks/fish_config.fish
@@ -1,7 +1,10 @@
 #RUN: %fish %s
 
 mkdir $__fish_config_dir/themes
-echo >$__fish_config_dir/themes/foo.theme 'fish_color_normal cyan'
+echo >$__fish_config_dir/themes/foo.theme '
+fish_color_normal cyan
+fish_color_error brred --underline=curly
+'
 
 set -g fish_pager_color_secondary_background custom-value
 fish_config theme choose foo
@@ -12,6 +15,14 @@ set -S fish_color_normal
 set -S fish_pager_color_secondary_background
 # CHECK: $fish_pager_color_secondary_background: set in global scope, unexported, with 0 elements
 
+# Not a default theme, so we allow --underline=curly even if we don't run inside a terminal that
+# advertises support via XTGETTCAP.
+set -S fish_color_error
+# CHECK: $fish_color_error: set in global scope, unexported, with 2 elements
+# CHECK: $fish_color_error[1]: |brred|
+# CHECK: $fish_color_error[2]: |--underline=curly|
+
+
 function change-theme
     echo >$__fish_config_dir/themes/fake-default.theme 'fish_color_command' $argv
 end