I made the small change suggested by Guillaume on the development branch here (http://hg.savannah.gnu.org/hgweb/octave/rev/a5924b0cbf42).  This is only a partial fix until, or if, this feature can actually be implemented.

I've changed the bug title to reflect the fact that "MonitorPositions" is still not fully implemented, and lowered the priority.

Guillamue, the disadvantage with that approach is that it would make the property handling "irregular", unless "MonitorPositions" is added as a new property.

I think that one of the reasons that Octave's graphics is so painfully slow is that too many objects have too many parameter.  Although they're normally left at their default values, they still need to be allocated and copied and deleted way too many times.

I think that there needs to be a rewrite of the graphics system that just keeps a pointer to the default values of the suitable type, and has a small list of non-default parameters for each particular object.

Once that is done, it will be cheap to add new properties.

This should be moot since this property is only valid for "root" (of which there is only one), but I recall seeing somewhere that all objects store all properties, with some simply being ignored depending on the type.  I hope I'm mistaken :)

Octave does not yet implement the MonitorPositions property.  Would it be reasonable to return

[NA NA NA NA]

to indicate that Octave does not use this?