diff --git a/scripts/gui-session.sh b/scripts/gui-session.sh
new file mode 100755
index 0000000000..9bf44d076f
--- /dev/null
+++ b/scripts/gui-session.sh
@@ -0,0 +1,125 @@
+#!/usr/bin/env bash
+# Bring the headless GUI up on a VNC-served X display, ready to drive or to attach Remmina to.
+#
+# Runs INSIDE the long-lived GUI container (see the header of scripts/docker-iter-build.sh for how
+# that container is created). Idempotent: safe to re-run to recover a session whose app died.
+#
+#   docker exec <container> /OrcaSlicer/scripts/gui-session.sh          # launch + settle
+#   docker exec <container> /OrcaSlicer/scripts/gui-session.sh --status # report, change nothing
+#
+# WHY THIS EXISTS. Dismissing the first-run dialogs by computing the titlebar close box from
+# `xdotool getwindowgeometry --shell` and clicking it went wrong whenever the dialog had already
+# closed: the eval left the geometry variables stale or empty, the click landed at a garbage
+# coordinate, and it repeatedly hit the Sketch button in the toolbar underneath, so the app came up
+# in sketch mode with a stray Sketch feature. Three of those in one session.
+#
+# The titlebar click is nevertheless the RIGHT mechanism and is kept. `xdotool windowclose` looks
+# cleaner but kills the app: it destroys the GdkWindow out from under the dialog and the process
+# dies with "GdkWindow unexpectedly destroyed", three GLib-GObject criticals and a segfault
+# (measured 2026-07-30). Escape does not close the Setup Wizard either. So the fix is not a
+# different mechanism, it is refusing to click on geometry we have not validated.
+set -euo pipefail
+
+DISP="${DISP:-:11}"
+GEOM="${GEOM:-1920x1080}"
+BIN="${BIN:-/OrcaSlicer/build/src/Release/orca-slicer}"
+# Packaging cannot bundle python (the deps python layer carries a doubled-DESTDIR RUNPATH), so the
+# build-tree binary needs the deps libpython on the path. Packaging-only issue; the app runs fine.
+LIBPY="/OrcaSlicer/deps/build/destdir/usr/local/libpython/lib"
+LIBPY2="/OrcaSlicer/build/src/Release/python/lib"
+LOG="${LOG:-/tmp/gui-session.log}"
+
+export DISPLAY="$DISP" HOME=/root
+export LIBGL_ALWAYS_SOFTWARE=1 GALLIUM_DRIVER=llvmpipe
+export LD_LIBRARY_PATH="$LIBPY:$LIBPY2:${LD_LIBRARY_PATH:-}"
+mkdir -p /root/.config          # startup dies in boost::filesystem::create_directory without this
+
+# Skip zombies. This container accumulates <defunct> instances of the app across runs, and pgrep
+# matches them, so the naive "first match" reported a dead pid as if the session were healthy.
+app_pid() {
+    local p
+    for p in $(pgrep -f "$(basename "$BIN")" 2>/dev/null); do
+        [ "$(awk "{print \$3}" "/proc/$p/stat" 2>/dev/null)" = "Z" ] && continue
+        echo "$p"; return 0
+    done
+    return 1
+}
+
+status() {
+    echo "display : $(pgrep -f "Xvfb $DISP" >/dev/null && echo up || echo DOWN)"
+    echo "wm      : $(pgrep -x openbox   >/dev/null && echo up || echo DOWN)"
+    if pgrep -x x11vnc >/dev/null; then echo "vnc     : up on :5900"
+    elif ! command -v x11vnc >/dev/null; then echo "vnc     : n/a (x11vnc not installed here)"
+    else echo "vnc     : DOWN"; fi
+    local p; p="$(app_pid || true)"
+    echo "app     : ${p:-DOWN}"
+    [ -n "${p:-}" ] && echo "windows : $(xdotool search --name . getwindowname %@ 2>/dev/null | paste -sd'|' -)"
+    return 0
+}
+
+[ "${1:-}" = "--status" ] && { status; exit 0; }
+
+# --- desktop: Xvfb, a window manager, and the VNC server ------------------------------------
+# openbox is REQUIRED: without it xdotool windowactivate aborts with "windowmanager claims not to
+# support _NET_ACTIVE_WINDOW" and dialogs never take focus.
+pgrep -f "Xvfb $DISP" >/dev/null || { nohup Xvfb "$DISP" -screen 0 "${GEOM}x24" -nolisten tcp >/tmp/xvfb.log 2>&1 & sleep 3; }
+pgrep -x openbox      >/dev/null || { nohup openbox >/tmp/openbox.log 2>&1 & sleep 1; }
+if ! pgrep -x x11vnc >/dev/null && command -v x11vnc >/dev/null; then
+    AUTH=()
+    [ -f /root/.vnc/passwd ] && AUTH=(-rfbauth /root/.vnc/passwd)
+    nohup x11vnc -display "$DISP" -rfbport 5900 "${AUTH[@]}" -forever -shared -noxdamage \
+        >/tmp/x11vnc.log 2>&1 &
+    sleep 2
+fi
+
+# --- app ------------------------------------------------------------------------------------
+pkill -9 -f "$BIN" 2>/dev/null || true
+sleep 2
+nohup "$BIN" >"$LOG" 2>&1 &
+echo "launched $(basename "$BIN") pid $!"
+
+# Wait for the main window rather than sleeping a fixed amount: cold starts vary a lot under
+# software GL, and a fixed sleep either wastes time or races.
+for _ in $(seq 1 40); do
+    xdotool search --name "Untitled" >/dev/null 2>&1 && break
+    sleep 1
+done
+
+# --- first-run dialogs ----------------------------------------------------------------------
+# Click the titlebar close box, but only on geometry we have just read for a window that still
+# exists, and only if the resulting point is inside the screen. Every variable is unset first so a
+# failed read cannot leave the previous dialog's numbers behind — that is the whole bug.
+screen_w="${GEOM%x*}"; screen_h="${GEOM#*x}"
+close_dialog() {
+    local name="$1" id X Y WIDTH HEIGHT cx cy
+    id="$(xdotool search --name "$name" 2>/dev/null | head -1 || true)"
+    [ -z "$id" ] && return 1
+    unset X Y WIDTH HEIGHT
+    eval "$(xdotool getwindowgeometry --shell "$id" 2>/dev/null || true)"
+    # All four must be present and numeric: an empty or stale read is how the stray click happened.
+    for v in "${X:-}" "${Y:-}" "${WIDTH:-}" "${HEIGHT:-}"; do
+        [[ "$v" =~ ^-?[0-9]+$ ]] || { echo "  $name: unreadable geometry, not clicking"; return 1; }
+    done
+    cx=$((X + WIDTH - 11)); cy=$((Y - 31))          # openbox decoration: close box above the frame
+    if [ "$cx" -lt 0 ] || [ "$cy" -lt 0 ] || [ "$cx" -ge "$screen_w" ] || [ "$cy" -ge "$screen_h" ]; then
+        echo "  $name: close box at ${cx},${cy} is off-screen, not clicking"; return 1
+    fi
+    echo "  $name: closing via titlebar at ${cx},${cy}"
+    xdotool mousemove "$cx" "$cy" click 1
+    sleep 2
+    return 0
+}
+for name in "Setup Wizard" "New version"; do
+    for _ in 1 2 3; do close_dialog "$name" || break; done
+done
+
+# --- main window ----------------------------------------------------------------------------
+main="$(xdotool search --name "Untitled" 2>/dev/null | head -1 || true)"
+if [ -n "$main" ]; then
+    xdotool windowmove "$main" 0 0 windowsize "$main" ${GEOM/x/ } 2>/dev/null || true
+    xdotool windowactivate "$main" 2>/dev/null || true
+    sleep 2
+fi
+
+echo "--- session ---"
+status