diff --git a/xpra/gtk/configure/gstreamer.py b/xpra/gtk/configure/gstreamer.py
index dd358cc013..070b1954f2 100644
--- a/xpra/gtk/configure/gstreamer.py
+++ b/xpra/gtk/configure/gstreamer.py
@@ -4,9 +4,11 @@
 # later version. See the file COPYING for details.
 
 import gi
+from textwrap import wrap
 
 from xpra.gtk.dialogs.base_gui_window import BaseGUIWindow
 from xpra.gtk.widget import label
+from xpra.platform.paths import get_icon
 from xpra.log import Logger
 
 gi.require_version('Gtk', '3.0')
@@ -14,21 +16,73 @@
 
 log = Logger("gstreamer", "util")
 
+DISCLAIMER = """
+IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING,
+BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT(INCLUDING NEGLIGENCE
+OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+""".replace("\n", "")
 
 class ConfigureGUI(BaseGUIWindow):
 
     def __init__(self, parent:Gtk.Window|None=None):
+        self.warning_shown = False
+        self.warning_pixbuf = get_icon("warning.png")
+        size = (800, 554)
+        if self.warning_pixbuf:
+            size = self.warning_pixbuf.get_width(), self.warning_pixbuf.get_height()
         super().__init__(
             "Configure Xpra's GStreamer Codecs",
             "gstreamer.png",
             wm_class=("xpra-configure-gstreamer-gui", "Xpra Configure GStreamer GUI"),
-            default_size=(640, 300),
+            default_size=size,
             header_bar=(True, False),
             parent=parent,
         )
+        self.set_resizable(False)
 
     def populate(self):
-        self.add_widget(label("Configure Xpra GStreamer Codecs", font="sans 20"))
+        for x in self.vbox.get_children():
+            self.vbox.remove(x)
+        if not self.warning_shown:
+            self.populate_with_warning()
+        else:
+            self.add_widget(label("Configure Xpra GStreamer Codecs", font="sans 20"))
+        self.vbox.show_all()
+
+    def populate_with_warning(self):
+        layout = Gtk.Layout()
+        self.vbox.add(layout)
+        pixbuf = get_icon("warning.png")
+        image = Gtk.Image.new_from_pixbuf(pixbuf)
+        layout.put(image, 0, 0)
+        for i, text in enumerate((
+            "This tool can cause your system to crash,",
+            "it may even damage hardware in rare cases.",
+            "            Use with caution.",
+        )):
+            lbl = label(text, font="Sans 22")
+            layout.put(lbl, 86, 70+i*40)
+        for i, line in enumerate(wrap(DISCLAIMER, width=70)):
+            lbl = label(line, font="Sans 12")
+            layout.put(lbl, 72, 220+i*24)
+        button = Gtk.Button.new_with_label("Understood")
+        button.connect("clicked", self.understood)
+        layout.put(button, 200, 450)
+        button = Gtk.Button.new_with_label("Get me out of here")
+        button.connect("clicked", self.dismiss)
+        layout.put(button, 400, 450)
+        self.warning_shown = True
+
+    def understood(self, *args):
+        self.warning_shown = True
+        self.populate()
+
+    def show(self):
+        super().show()
 
 
 def main() -> int:
diff --git a/xpra/gtk/dialogs/base_gui_window.py b/xpra/gtk/dialogs/base_gui_window.py
index 4e50cdca8c..754f5e84e1 100644
--- a/xpra/gtk/dialogs/base_gui_window.py
+++ b/xpra/gtk/dialogs/base_gui_window.py
@@ -71,11 +71,11 @@ def __init__(self,
         if parent:
             self.set_transient_for(parent)
             self.set_modal(True)
-            close = self.hide
+            self.do_dismiss = self.hide
         else:
-            close = self.quit
-        self.connect("delete_event", close)
-        add_close_accel(self, close)
+            self.do_dismiss = self.quit
+        self.connect("delete_event", self.dismiss)
+        add_close_accel(self, self.dismiss)
         add_window_accel(self, 'F1', self.show_about)
         with IgnoreWarningsContext():
             self.set_wmclass(*wm_class)
@@ -87,6 +87,11 @@ def __init__(self,
         self.connect("focus-in-event", self.focus_in)
         self.connect("focus-out-event", self.focus_out)
 
+    def dismiss(self, *args):
+        log(f"dismiss{args} calling {self.do_dismiss}")
+        self.do_dismiss()
+
+
     def add_headerbar(self, about=True, toolbox=True):
         hb = Gtk.HeaderBar()
         hb.set_show_close_button(True)