gtk:window-set-interactive-debugging (enable)

enable -- true to enable interactice debugging

Opens or closes the interactive debugger. The debugger offers access to the widget hierarchy of the application and to useful debugging tools.

There is the "enable-debugging" signal which gets emitted when the user enables or disables interactive debugging. The default bindings are the Ctrl-Shift-I or Ctrl-Shift-D keys, which starts the GTK-Inspector.