Gets or sets whether this item should expand to fill the maximum available width (only applies to Panel buttons).
true if this item should expand to fill the maximum available width; otherwise, false.
Setting this property to true on a Panel button causes the panel's width to automatically fill the available space on a band. The width of the child control, if one is assigned, will also fill the available space. One example of this is the address box in Microsoft Internet Explorer.
When this property is true, the Width property specifies the minimum width to which the panel will be resized.
RebarButton Class | Skybound.Rebar Namespace