The 'SCRIBBLE' mnemonic toggles scribble mode on and off. By default, scribble mode is off. The option to turn scribble mode on is:
When scribble mode is enabled, the draw panel intercepts the relevant mouse or touch events and draws lines using the current PENWIDTH, PENCOLOR, PATTERN, and DRAWMODE settings. This mode is typically used to facilitate signature capture and similar features. Caveat: The server knows nothing about lines drawn directly on the client, so they are discarded if the draw panel is reset from the server with the REDRAW command.