Variable: x-gtk-use-system-tooltips
x-gtk-use-system-tooltips is an alias and customizable for
use-system-tooltips, defined in cider-mode.el.
Value
t
Documentation
Whether to use the toolkit to display tooltips.
This option is only meaningful when Emacs is built with GTK+, NS or Haiku windowing support, and, if it's non-nil (the default), it results in tooltips that look like those displayed by other GTK+/NS/Haiku programs, but will not be able to display text properties inside tooltip text.
Probably introduced at or before Emacs version 24.1.