Gtk.Settings:gtk-tooltip-browse-timeout
"gtk-tooltip-browse-timeout" Number : Read / Write
Controls the time after which tooltips will appear when browse mode is enabled, in milliseconds.
Browse mode is enabled when the mouse pointer moves off an object where a tooltip was currently being displayed. If the mouse pointer hits another object before the browse mode timeout expires (see Gtk.Settings:gtk-tooltip-browse-mode-timeout), it will take the amount of milliseconds specified by this setting to popup the tooltip for the new object.
Since 2.12