set-label in frame:editor-mixin

Sets a window's label. The window's natural minimum size might be different after the label is changed, but the window's minimum size is not recomputed.

See get-label for more information.

• (send a-frame:editor-mixin set-label l) -> void
     l : string (up to 200 characters) or #f

  If l is #f, the window's label is removed.

  Sets the label, but preserve's the label's prefix. See also set-label-prefix.