I am getting the same X protocol error (BadRequest 131) but I don't see anything related to the tooltips in the stack trace. The easiest way to trigger the error is to click on the toolbar (I clicked on the file manager icon to get the trace below).
Alex
$ emacs --no-init
** (emacs:16227): WARNING **: Error retrieving accessibility bus address: org.freedesktop.DBus.Error.ServiceUnknown: The name org.a11y.Bus was not provided by any .se
rvice files
Fontconfig warning: line 142: blank doesn't take any effect anymore. please remove it from your fonts.conf
(emacs:16227): GLib-GIO-CRITICAL **: g_settings_schema_source_lookup: assertion 'source != NULL' failed
X protocol error: BadRequest (invalid request code or no such operation) on protocol request 131
When compiled with GTK, Emacs cannot recover from X disconnects.
For details, see etc/PROBLEMS.
Fatal error 6: Aborted
Backtrace:
emacs[0x509edc]
emacs[0x4ef82b]
emacs[0x5095d3]
emacs[0x4c340b]
emacs[0x4c36f6]
emacs[0x4c377b]
/nix/store/dcjg6hrk8061gbyrvwqlrbpd17xxzckc-libX11-1.6.4/lib/libX11.so.6(_XError+0x11d)[0x7fd4bee400bd]
/nix/store/dcjg6hrk8061gbyrvwqlrbpd17xxzckc-libX11-1.6.4/lib/libX11.so.6(+0x41fb7)[0x7fd4bee3cfb7]
/nix/store/dcjg6hrk8061gbyrvwqlrbpd17xxzckc-libX11-1.6.4/lib/libX11.so.6(+0x42075)[0x7fd4bee3d075]
/nix/store/dcjg6hrk8061gbyrvwqlrbpd17xxzckc-libX11-1.6.4/lib/libX11.so.6(_XReply+0x238)[0x7fd4bee3df98]
/nix/store/dcjg6hrk8061gbyrvwqlrbpd17xxzckc-libX11-1.6.4/lib/libX11.so.6(XQueryPointer+0x8e)[0x7fd4bee340ae]
/nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgdk-3.so.0(+0x57cea)[0x7fd4c0c88cea]
/nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgdk-3.so.0(+0x766f5)[0x7fd4c0ca76f5]
/nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgdk-3.so.0(gdk_window_get_device_position_double+0x10d)[0x7fd4c0c7af1d]
/nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgdk-3.so.0(gdk_window_get_device_position+0x2d)[0x7fd4c0c7b02d]
/nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgtk-3.so.0(+0x33d359)[0x7fd4c1258359]
/nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgtk-3.so.0(+0x33d8ef)[0x7fd4c12588ef]
/nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgdk-3.so.0(+0x2ae78)[0x7fd4c0c5be78]
/nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libglib-2.0.so.0(+0x4a663)[0x7fd4bf5ab663]
/nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libglib-2.0.so.0(g_main_context_dispatch+0x15a)[0x7fd4bf5aabfa]
emacs[0x5df9c8]
emacs[0x5ab6e3]
emacs[0x420ef5]
emacs[0x4fbf41]
emacs[0x4fcb6b]
emacs[0x4fe8ee]
emacs[0x564656]
emacs[0x4efd14]
emacs[0x5645db]
emacs[0x4efcbd]
emacs[0x4f2ee3]
emacs[0x4f3223]
emacs[0x416f74]
/nix/store/a5gvhlwrday3dj8z3v09nr65ngn5jzq3-glibc-2.25/lib/libc.so.6(__libc_start_main+0xf0)[0x7fd4bbddd530]
emacs[0x417cda]
Aborted (core dumped)
(gdb) bt
#0 0x00007ffff502d731 in _g_log_abort () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libglib-2.0.so.0
#1 0x00007ffff502e7bc in g_log_default_handler () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libglib-2.0.so.0
#2 0x00007ffff502eae4 in g_logv () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libglib-2.0.so.0
#3 0x00007ffff502ecef in g_log () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libglib-2.0.so.0
#4 0x00007ffff564bdb2 in g_settings_set_property () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgio-2.0.so.0
#5 0x00007ffff530717b in g_object_new_internal () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#6 0x00007ffff5308a53 in g_object_new_valist () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#7 0x00007ffff5308fa1 in g_object_new () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#8 0x00007ffff6b5b32c in _gtk_file_chooser_get_settings_for_widget () from /nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgtk-3.so.0
#9 0x00007ffff6b5e820 in gtk_file_chooser_widget_get_default_size () from /nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgtk-3.so.0
#10 0x00007ffff6b56e54 in file_chooser_widget_default_size_changed () from /nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgtk-3.so.0
#11 0x00007ffff5301a85 in g_closure_invoke () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#12 0x00007ffff5313a71 in signal_emit_unlocked_R () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#13 0x00007ffff531c81c in g_signal_emit_valist () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#14 0x00007ffff531d015 in g_signal_emit_by_name () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#15 0x00007ffff6b64d24 in update_appearance () from /nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgtk-3.so.0
#16 0x00007ffff6b65026 in gtk_file_chooser_widget_set_property () from /nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgtk-3.so.0
#17 0x00007ffff5309d6b in g_object_set_property () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#18 0x00007ffff53071e9 in g_object_new_internal () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#19 0x00007ffff5308a53 in g_object_new_valist () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#20 0x00007ffff5308fa1 in g_object_new () from /nix/store/x7h9j1ka9kpkrl7z9vs7llqk7j0xjc52-glib-2.50.3/lib/libgobject-2.0.so.0
#21 0x00007ffff6b576a4 in gtk_file_chooser_dialog_new () from /nix/store/08aszpny14726520h4vzxbkdi3m3j4gb-gtk+3-3.22.8/lib/libgtk-3.so.0
#22 0x00000000004de2c0 in xg_get_file_with_chooser ()
#23 0x00000000004e1868 in xg_get_file_name ()
#24 0x00000000004cede4 in Fx_file_dialog ()
#25 0x0000000000565ff7 in Ffuncall ()
#26 0x000000000059f163 in exec_byte_code ()
#27 0x0000000000565e2b in Ffuncall ()
#28 0x000000000059f163 in exec_byte_code ()
#29 0x0000000000565e2b in Ffuncall ()
#30 0x000000000059f163 in exec_byte_code ()
#31 0x0000000000565e2b in Ffuncall ()
#32 0x000000000059f163 in exec_byte_code ()
#33 0x0000000000564f3b in apply_lambda ()
#34 0x00000000005652b6 in eval_sub ()
#35 0x0000000000568ac7 in Feval ()
#36 0x0000000000562103 in Fcall_interactively ()
#37 0x0000000000566023 in Ffuncall ()
#38 0x000000000059f163 in exec_byte_code ()
#39 0x0000000000565e2b in Ffuncall ()
#40 0x000000000056613a in call1 ()
#41 0x00000000004feaf8 in command_loop_1 ()
#42 0x0000000000564656 in internal_condition_case ()
#43 0x00000000004efd14 in command_loop_2 ()
#44 0x00000000005645db in internal_catch ()
#45 0x00000000004efcbd in command_loop ()
---Type <return> to continue, or q <return> to quit---
#46 0x00000000004f2ee3 in recursive_edit_1 ()
#47 0x00000000004f3223 in Frecursive_edit ()
#48 0x0000000000416f74 in main ()