only seems to work reliably with python3

git-svn-id: https://xpra.org/svn/Xpra/trunk@20941 3bb7dfac-3a0b-4e04-842a-767bc560f471

src/xpra/client/mixins/window_manager.py

@@ -35,7 +35,7 @@
 from xpra.platform.paths import get_icon_filename
 from xpra.scripts.config import FALSE_OPTIONS
 from xpra.make_thread import make_thread
-from xpra.os_util import BytesIOClass, Queue, bytestostr, monotonic_time, memoryview_to_bytes, OSX, POSIX, is_Ubuntu
+from xpra.os_util import BytesIOClass, Queue, bytestostr, monotonic_time, memoryview_to_bytes, OSX, POSIX, PYTHON3, is_Ubuntu
 from xpra.util import iround, envint, envbool, typedict, make_instance, updict
 from xpra.client.mixins.stub_client_mixin import StubClientMixin
 
@@ -68,7 +68,7 @@
 SAVE_WINDOW_ICONS = envbool("XPRA_SAVE_WINDOW_ICONS", False)
 SAVE_CURSORS = envbool("XPRA_SAVE_CURSORS", False)
 MODAL_WINDOWS = envbool("XPRA_MODAL_WINDOWS", False)
-SIGNAL_WATCHER = envbool("XPRA_SIGNAL_WATCHER", True)
+SIGNAL_WATCHER = envbool("XPRA_SIGNAL_WATCHER", PYTHON3)
 
 
 DRAW_TYPES = {bytes : "bytes", str : "bytes", tuple : "arrays", list : "arrays"}