Weird behavior of rounded corners

[pandasoli]

Platform:

Gentoo GNU/Linux
Kernel: 6.1.55-gentoo-dist

I'm using xmonad as window manager.

GPU, drivers, and screen setup:

I'm a noobie on Gentoo yet.
I know in Arch I installed drivers for video but here I don't have any, and everything just works fine.
equery list \* | grep intel just returns the microcode

Compton version:

Compton: v10
Picom: v10

Compton configuration:

Click to open up my config

#################################
#             Corners           #
#################################
# requires: https://github.com/sdhand/compton
corner-radius = 12;
rounded-corners-exclude = [
  #"window_type = 'normal'",
  "class_g = 'Rofi'",
  #"class_g = 'Tint2'",
  "name = 'Notification area'",
  #"class_g = 'kitty'",
  #"class_g = 'Alacritty'",
  "class_g = 'Polybar'",
  "class_g = 'code-oss'",
  "class_g = 'firefox'",
  "class_g = 'Thunderbird'"
];
round-borders = 1;
round-borders-exclude = [
  #"class_g = 'TelegramDesktop'",
];

# Specify a list of border width rules, in the format `PIXELS:PATTERN`, 
# Note we don't make any guarantee about possible conflicts with the
# border_width set by the window manager.
#
# example:
#    round-borders-rule = [ "2:class_g = 'URxvt'" ];
#
round-borders-rule = [
  "3:class_g      = 'XTerm'",
  "3:class_g      = 'URxvt'",
  #"10:class_g     = 'Alacritty'",
  "15:class_g     = 'Signal'"
];

#################################
#             Shadows           #
#################################


# Enabled client-side shadows on windows. Note desktop windows 
# (windows with '_NET_WM_WINDOW_TYPE_DESKTOP') never get shadow, 
# unless explicitly requested using the wintypes option.
#
 shadow = false
#shadow = true;

# The blur radius for shadows, in pixels. (defaults to 12)
# shadow-radius = 12
shadow-radius = 12;

# The opacity of shadows. (0.0 - 1.0, defaults to 0.75)
shadow-opacity = 0.75

# The left offset for shadows, in pixels. (defaults to -15)
# shadow-offset-x = -15
shadow-offset-x = -15;

# The top offset for shadows, in pixels. (defaults to -15)
# shadow-offset-y = -15
shadow-offset-y = -15;

# Avoid drawing shadows on dock/panel windows. This option is deprecated,
# you should use the *wintypes* option in your config file instead.
#
# no-dock-shadow = false

# Don't draw shadows on drag-and-drop windows. This option is deprecated, 
# you should use the *wintypes* option in your config file instead.
#
# no-dnd-shadow = false

# Red color value of shadow (0.0 - 1.0, defaults to 0).
# shadow-red = 0

# Green color value of shadow (0.0 - 1.0, defaults to 0).
# shadow-green = 0

# Blue color value of shadow (0.0 - 1.0, defaults to 0).
# shadow-blue = 0

# Do not paint shadows on shaped windows. Note shaped windows 
# here means windows setting its shape through X Shape extension. 
# Those using ARGB background is beyond our control. 
# Deprecated, use 
#   shadow-exclude = 'bounding_shaped'
# or 
#   shadow-exclude = 'bounding_shaped && !rounded_corners'
# instead.
#
# shadow-ignore-shaped = ''

# Specify a list of conditions of windows that should have no shadow.
#
# examples:
#   shadow-exclude = "n:e:Notification";
#
# shadow-exclude = []
shadow-exclude = [
  "name = 'Notification'",
  "class_g = 'Conky'",
  "class_g ?= 'Notify-osd'",
  "class_g = 'Cairo-clock'",
  "class_g = 'slop'",
  "class_g = 'Polybar'",
  "_GTK_FRAME_EXTENTS@:c"
];

# Specify a X geometry that describes the region in which shadow should not
# be painted in, such as a dock window region. Use 
#    shadow-exclude-reg = "x10+0+0"
# for example, if the 10 pixels on the bottom of the screen should not have shadows painted on.
#
# shadow-exclude-reg = "" 

# Crop shadow of a window fully on a particular Xinerama screen to the screen.
# xinerama-shadow-crop = false


#################################
#           Fading              #
#################################

# Fade windows in/out when opening/closing and when opacity changes,
#  unless no-fading-openclose is used.
# fading = false
fading = true;

# Opacity change between steps while fading in. (0.01 - 1.0, defaults to 0.028)
# fade-in-step = 0.028
fade-in-step = 0.015;

# Opacity change between steps while fading out. (0.01 - 1.0, defaults to 0.03)
# fade-out-step = 0.03
fade-out-step = 0.1;

# The time between steps in fade step, in milliseconds. (> 0, defaults to 10)
fade-delta = 10

# Specify a list of conditions of windows that should not be faded.
# don't need this, we disable fading for all normal windows with wintypes: {}
fade-exclude = [
  #"class_g = 'slop'"   # maim
]

# Do not fade on window open/close.
# no-fading-openclose = false

# Do not fade destroyed ARGB windows with WM frame. Workaround of bugs in Openbox, Fluxbox, etc.
# no-fading-destroyed-argb = false


#################################
#   Transparency / Opacity      #
#################################


# Opacity of inactive windows. (0.1 - 1.0, defaults to 1.0)
# inactive-opacity = 1
inactive-opacity = 1;

# Opacity of window titlebars and borders. (0.1 - 1.0, disabled by default)
# frame-opacity = 1.0
frame-opacity = 1.0;

# Default opacity for dropdown menus and popup menus. (0.0 - 1.0, defaults to 1.0)
# menu-opacity = 1.0

# Let inactive opacity set by -i override the '_NET_WM_OPACITY' values of windows.
# inactive-opacity-override = true
inactive-opacity-override = false;

# Default opacity for active windows. (0.0 - 1.0, defaults to 1.0)
active-opacity = 1;

# Dim inactive windows. (0.0 - 1.0, defaults to 0.0)
# inactive-dim = 0.0

# Specify a list of conditions of windows that should always be considered focused.
# focus-exclude = []
focus-exclude = [
  "class_g = 'Cairo-clock'",
  "class_g = 'Bar'",                    # lemonbar
  "class_g = 'slop'"                    # maim
];

# Use fixed inactive dim value, instead of adjusting according to window opacity.
# inactive-dim-fixed = 1.0

# Specify a list of opacity rules, in the format `PERCENT:PATTERN`, 
# like `50:name *= "Firefox"`. picom-trans is recommended over this. 
# Note we don't make any guarantee about possible conflicts with other 
# programs that set '_NET_WM_WINDOW_OPACITY' on frame or client windows.
# example:
#    opacity-rule = [ "80:class_g = 'URxvt'" ];
#
# opacity-rule = []
opacity-rule = [
   "100:name     = 'Dunst'",             # lemonbar
  "10:class_g    = 'eww-blur_full'",            # maim
  #"100:class_g    = 'XTerm'",
  #"100:class_g    = 'URxvt'",
  #"75:class_g    = 'Alacritty'",
  #"60:class_g    = 'eww-player'",
  "100:class_g    = 'Tint2'"
  #"80:class_g     = 'Polybar'",
  #"100:class_g    = 'code-oss'",
  #"100:class_g    = 'Meld'",
  #"70:class_g     = 'TelegramDesktop'",
  #"90:class_g     = 'Joplin'",
  #"100:class_g    = 'firefox'",
  #"80:class_g    = 'Spotify'"
];


#################################
#     Background-Blurring       #
#################################


# Parameters for background blurring, see the *BLUR* section for more information.
# blur-method = "dual_kawase"
# blur-size = 12
#
# blur-deviation = false

# Blur background of semi-transparent / ARGB windows. 
#
# blur-background = true;

# Blur background of windows when the window frame is not opaque. 
# Implies:
#    blur-background 
# Bad in performance, with driver-dependent behavior. The name may change.
#
# blur-background-frame = false;


# Use fixed blur strength rather than adjusting according to window opacity.
# blur-background-fixed = false;


# Specify the blur convolution kernel, with the following format:
# example:
#   blur-kern = "5,5,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1";
#
# blur-kern = ''
# blur-kern = "3x3box";

blur: {
  # requires: https://github.com/ibhagwan/picom
  method = "dual_kawase";
  #method = "kernel";
  strength = 6;
  deviation = 1.0;
  # kernel = "11x11gaussian";
  background = false;
  background-frame = false;
  background-fixed = false;
  kern = "3x3box";
}

# Exclude conditions for background blur.
blur-background-exclude = [
  #"window_type = 'dock'",
  #"window_type = 'desktop'",
  #"class_g = 'URxvt'",
  "class_g = 'dwm'",
  #
  # prevents picom from blurring the background
  # when taking selection screenshot with `main`
  # https://github.com/naelstrof/maim/issues/130
  "class_g = 'slop'",
  "_GTK_FRAME_EXTENTS@:c"
];


#################################
#       General Settings        #
#################################

# Daemonize process. Fork to background after initialization. Causes issues with certain (badly-written) drivers.
# daemon = false

# Specify the backend to use: `xrender`, `glx`, or `xr_glx_hybrid`.
# `xrender` is the default one.
#
experimental-backends = true;
backend = "glx";
#backend = "xrender";


# Enable/disable VSync.
# vsync = false
vsync = true

# Enable remote control via D-Bus. See the *D-BUS API* section below for more details.
# dbus = false

# Try to detect WM windows (a non-override-redirect window with no 
# child that has 'WM_STATE') and mark them as active.
#
# mark-wmwin-focused = false
mark-wmwin-focused = true;

# Mark override-redirect windows that doesn't have a child window with 'WM_STATE' focused.
# mark-ovredir-focused = false
mark-ovredir-focused = true;

# Try to detect windows with rounded corners and don't consider them 
# shaped windows. The accuracy is not very high, unfortunately.
#
# detect-rounded-corners = false
detect-rounded-corners = true

# Detect '_NET_WM_OPACITY' on client windows, useful for window managers
# not passing '_NET_WM_OPACITY' of client windows to frame windows.
#
# detect-client-opacity = false
detect-client-opacity = true;

# Specify refresh rate of the screen. If not specified or 0, picom will 
# try detecting this with X RandR extension.
#
# refresh-rate = 60
refresh-rate = 0

# Limit picom to repaint at most once every 1 / 'refresh_rate' second to 
# boost performance. This should not be used with 
#   vsync drm/opengl/opengl-oml
# as they essentially does sw-opti's job already, 
# unless you wish to specify a lower refresh rate than the actual value.
#
# sw-opti = 

# Use EWMH '_NET_ACTIVE_WINDOW' to determine currently focused window, 
# rather than listening to 'FocusIn'/'FocusOut' event. Might have more accuracy, 
# provided that the WM supports it.
#
# use-ewmh-active-win = false

# Unredirect all windows if a full-screen opaque window is detected, 
# to maximize performance for full-screen windows. Known to cause flickering 
# when redirecting/unredirecting windows. paint-on-overlay may make the flickering less obvious.
#
# unredir-if-possible = false

# Delay before unredirecting the window, in milliseconds. Defaults to 0.
# unredir-if-possible-delay = 0

# Conditions of windows that shouldn't be considered full-screen for unredirecting screen.
# unredir-if-possible-exclude = []

# Use 'WM_TRANSIENT_FOR' to group windows, and consider windows 
# in the same group focused at the same time.
#
# detect-transient = false
detect-transient = true

# Use 'WM_CLIENT_LEADER' to group windows, and consider windows in the same 
# group focused at the same time. 'WM_TRANSIENT_FOR' has higher priority if 
# detect-transient is enabled, too.
#
# detect-client-leader = false
detect-client-leader = true

# Resize damaged region by a specific number of pixels. 
# A positive value enlarges it while a negative one shrinks it. 
# If the value is positive, those additional pixels will not be actually painted 
# to screen, only used in blur calculation, and such. (Due to technical limitations, 
# with use-damage, those pixels will still be incorrectly painted to screen.) 
# Primarily used to fix the line corruption issues of blur, 
# in which case you should use the blur radius value here 
# (e.g. with a 3x3 kernel, you should use `--resize-damage 1`, 
# with a 5x5 one you use `--resize-damage 2`, and so on). 
# May or may not work with *--glx-no-stencil*. Shrinking doesn't function correctly.
#
# resize-damage = 1

# Specify a list of conditions of windows that should be painted with inverted color. 
# Resource-hogging, and is not well tested.
#
# invert-color-include = []

# GLX backend: Avoid using stencil buffer, useful if you don't have a stencil buffer. 
# Might cause incorrect opacity when rendering transparent content (but never 
# practically happened) and may not work with blur-background. 
# My tests show a 15% performance boost. Recommended.
#
# glx-no-stencil = false

# GLX backend: Avoid rebinding pixmap on window damage. 
# Probably could improve performance on rapid window content changes, 
# but is known to break things on some drivers (LLVMpipe, xf86-video-intel, etc.).
# Recommended if it works.
#
# glx-no-rebind-pixmap = false

# Disable the use of damage information. 
# This cause the whole screen to be redrawn everytime, instead of the part of the screen
# has actually changed. Potentially degrades the performance, but might fix some artifacts.
# The opposing option is use-damage
#
# no-use-damage = false
use-damage = true

# Use X Sync fence to sync clients' draw calls, to make sure all draw 
# calls are finished before picom starts drawing. Needed on nvidia-drivers 
# with GLX backend for some users.
#
# xrender-sync-fence = false

# GLX backend: Use specified GLSL fragment shader for rendering window contents. 
# See `compton-default-fshader-win.glsl` and `compton-fake-transparency-fshader-win.glsl` 
# in the source tree for examples.
#
# glx-fshader-win = ''

# Force all windows to be painted with blending. Useful if you 
# have a glx-fshader-win that could turn opaque pixels transparent.
#
# force-win-blend = false

# Do not use EWMH to detect fullscreen windows. 
# Reverts to checking if a window is fullscreen based only on its size and coordinates.
#
# no-ewmh-fullscreen = false

# Dimming bright windows so their brightness doesn't exceed this set value. 
# Brightness of a window is estimated by averaging all pixels in the window, 
# so this could comes with a performance hit. 
# Setting this to 1.0 disables this behaviour. Requires --use-damage to be disabled. (default: 1.0)
#
# max-brightness = 1.0

# Make transparent windows clip other windows like non-transparent windows do,
# instead of blending on top of them.
#
# transparent-clipping = false

# Set the log level. Possible values are:
#  "trace", "debug", "info", "warn", "error"
# in increasing level of importance. Case doesn't matter. 
# If using the "TRACE" log level, it's better to log into a file 
# using *--log-file*, since it can generate a huge stream of logs.
#
# log-level = "debug"
log-level = "info";

# Set the log file.
# If *--log-file* is never specified, logs will be written to stderr. 
# Otherwise, logs will to written to the given file, though some of the early 
# logs might still be written to the stderr. 
# When setting this option from the config file, it is recommended to use an absolute path.
#
# log-file = '/path/to/your/log/file'

# Show all X errors (for debugging)
# show-all-xerrors = false

# Write process ID to a file.
# write-pid-path = '/path/to/your/log/file'

# Window type settings
# 
# 'WINDOW_TYPE' is one of the 15 window types defined in EWMH standard: 
#     "unknown", "desktop", "dock", "toolbar", "menu", "utility", 
#     "splash", "dialog", "normal", "dropdown_menu", "popup_menu", 
#     "tooltip", "notification", "combo", and "dnd".
# 
# Following per window-type options are available: ::
# 
#   fade, shadow:::
#     Controls window-type-specific shadow and fade settings.
# 
#   opacity:::
#     Controls default opacity of the window type.
# 
#   focus:::
#     Controls whether the window of this type is to be always considered focused. 
#     (By default, all window types except "normal" and "dialog" has this on.)
# 
#   full-shadow:::
#     Controls whether shadow is drawn under the parts of the window that you 
#     normally won't be able to see. Useful when the window has parts of it 
#     transparent, and you want shadows in those areas.
# 
#   redir-ignore:::
#     Controls whether this type of windows should cause screen to become 
#     redirected again after been unredirected. If you have unredir-if-possible
#     set, and doesn't want certain window to cause unnecessary screen redirection, 
#     you can set this to `true`.
#
wintypes:
{
  normal = { full-shadow = true; };
  menu = { full-shadow = true; };
  tooltip = { fade = true; shadow = false; focus = true;};
  dock = { shadow = false; };
  dnd = { shadow = false; };
  popup_menu = { full-shadow = true; };
  utility = { full-shadow = true; };
  toolbar = { full-shadow = true; };
  notification = { opacity = 1; }
};

Steps of reproduction

Expected behavior

The border color be applied to the border.

Current Behavior & Other details

The border color is being applied to a triangle? with some opacity
The color is red but it has something like opacity, so it is hard to see. It looks a very light pink. Try giving a zoom!

Also: the white border color was not declared in my config file of Xmonad. So I don't know where is comes from.
My config sets #f00 to selected windows and #ccc for non selected.

Windows like firefox the rounded corners are not applied (dunno why) and the border color is correctly.

On this jorney of making pretty rounded corners I found out that I had to use GLX (not xrender), and to do this I had to recompile picom with support for it as compton (and picom) was saying it was compiled with no support.
Does it mean this project depends on picom installed?