Remove titlebar of maximized windows in GNOME3 (One for <=3.14 and one for >=3.16)

nomaxtitlebar-3.16.sh

#!/usr/bin/bash
#
# This script requires the command `wmctrl`!
#
# Execute this script at GNOME startup as a daemon (e.g. with the & control operator).
#
# It will check in an endless loop that all windows that are currently open have
# the _GTK_HIDE_TITLEBAR_WHEN_MAXIMIZED atom set to true.
#
 
check_hidden() {
    echo $(xprop -id $1 | grep "_GTK_HIDE_TITLEBAR_WHEN_MAXIMIZED(CARDINAL) = 1")
}

check_maximized() {
    echo $(xprop -id $1 | grep "_NET_WM_STATE_MAXIMIZED_HORZ, _NET_WM_STATE_MAXIMIZED_VERT")
}

while true; do
    known_windows=$(wmctrl -l | awk '{ print $1 }')

    for id in ${known_windows}; do
        if [ "$(check_hidden $id)" == "" ]; then
            xprop -id $id -f _GTK_HIDE_TITLEBAR_WHEN_MAXIMIZED 32c \
                -set _GTK_HIDE_TITLEBAR_WHEN_MAXIMIZED 0x1
            if [ "$(check_maximized $id)" != "" ]; then
                wmctrl -i -r $id -b toggle,maximized_vert,maximized_horz \
                && wmctrl -i -r $id -b toggle,maximized_vert,maximized_horz
            fi
        fi
    done

    sleep 0.5
done

nomaxtitlebar.sh

#!/usr/bin/bash
#
# This script takes the GNOME window (i.e. metacity) theme $THEME and creates a
# new theme called "$THEME-nomaxtitlebar" in the user's local theme directory.
#
# The new theme will be identical with $THEME apart from the fact that
# maximized windows won't have titlebars.
#
# You can activate the new theme by using gnome-tweak-tool or directly changing
# the dconf value "theme" in "org.gnome.desktop.wm.preferences".
#
# Effectively, you end up with the same result when using the maximus extension:
#    https://extensions.gnome.org/extension/354/maximus/
# But it seems to me like changing the window theme is the canonical solution.
#

THEME="Adwaita"
THEME_FILE="/usr/share/themes/$THEME/metacity-1/metacity-theme-3.xml"
OUTPUT_DIR="$HOME/.local/share/themes/$THEME-nomaxtitlebar/metacity-1"
OUTPUT_FILE="$OUTPUT_DIR/metacity-theme-3.xml"
TMP_FILE="$(mktemp)"

mkdir -p "$OUTPUT_DIR"

# At the moment, the XML file provided by GNOME isn't valid XML:
# https://bugzilla.gnome.org/show_bug.cgi?id=740889
# This is my temporary workaround:
sed 's/="\([^"]*\)<\([^"]*\)"/="\1\&lt;\2"/g' "$THEME_FILE" > "$OUTPUT_FILE"
sed 's/="\([^"]*\)>\([^"]*\)"/="\1\&gt;\2"/g' "$OUTPUT_FILE" > "$TMP_FILE"

rm "$OUTPUT_FILE"
xsltproc --nodtdattr -o "$OUTPUT_FILE" - "$TMP_FILE" << EOF
<xsl:stylesheet version="1.0"
      xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    
    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>
    
    <xsl:template match="frame_geometry[@name='max']">
        <xsl:copy>
            <xsl:attribute name="has_title">
                <xsl:text>false</xsl:text>
            </xsl:attribute>
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>
    
    <xsl:template match="@title_scale[parent::frame_geometry[@name='max']]">
    </xsl:template>
    
    <xsl:template match="frame_geometry[@name='max']/distance/@value">
        <xsl:attribute name="value">
            <xsl:text>0</xsl:text>
        </xsl:attribute>
    </xsl:template>
    
    <xsl:template match="frame_geometry[@name='max']/border">
        <xsl:copy>
            <xsl:attribute name="left">
                <xsl:text>0</xsl:text>
            </xsl:attribute>
            <xsl:attribute name="right">
                <xsl:text>0</xsl:text>
            </xsl:attribute>
            <xsl:attribute name="top">
                <xsl:text>0</xsl:text>
            </xsl:attribute>
            <xsl:attribute name="bottom">
                <xsl:text>0</xsl:text>
            </xsl:attribute>
            <xsl:apply-templates select="@name"/>
        </xsl:copy>
    </xsl:template>
    
</xsl:stylesheet>
EOF

# Unfortunately `xsltproc` replaces hexcode entities
sed 's/Â/\&#194;/g' "$OUTPUT_FILE" > "$TMP_FILE"

cp "$TMP_FILE" "$OUTPUT_FILE"
rm $TMP_FILE

I have tried to get rid of polling: https://gist.github.com/v6ak/b6e1c18b85ad2dc19c03cac1669b65d0

Maybe my script is too simple in some ways.