Gets a value indicating whether this AnnDrawDesigner is currently in extended mode.
Object.defineProperty(AnnDrawDesigner.prototype, 'isExtendedMode',
get: function()
)
isExtendedMode: boolean; // read-only // protected
true if this AnnDrawDesigner is currently in extended mode; otherwise, false.
This property will check if either the value of the ExtendedMode is set to true or the key specified by ExtendedModeModifierKey is currently being pressed.