drscheme:get/extend:extend-definitions-canvas in DrScheme Tools Functions
(drscheme:get/extend:extend-definitions-canvas-> void?mixin)
mixin: (make-mixin-contract drscheme:unit:definitions-canvas%)
(drscheme:get/extend:extend-definitions-canvas-> void?mixinbefore?)
mixin: (make-mixin-contract drscheme:unit:definitions-canvas%)
before?: boolean?This canvas is used in the top window of drscheme frames. The argument,
before, controls if the mixin is applied before or after already installed mixins. If unsupplied, this is the same as supplying#f.