Adds an actor as a child of this group, removing it from its previous parent. If the actor is already a child of this group, no changes are made.

rows is a seq of seqs of columns. Elements are actors or nil (for just adding empty cells ) or a map of {:actor :expand? :bottom? :colspan int :pad :pad-bottom}. Only :actor is required.

tooltip-text is a (fn []) or a string. If it is a function will be-recalculated every show.

The first checked button, or nil.

Returns true if the actor or its parent is a button.

on-clicked is a fn of one arg, taking the current isChecked state

Returns an ordered list of child actors in this group.

Removes all actors from this group and unfocuses them.

Takes either a texture-region or drawable. Opts are :scaling, :align and actor opts.

Creates a new drawable that renders the same as this drawable tinted the specified color.

Returns true if the actor is a window title bar.