columwidths so that in addition to numerical values also can accept a value of "nowrap". This will result in
<td style="white-space: nowrap">being added to the cells in question. "nowrap" as columnwidth essentially means to tell the browser to make the column wide enough not to wrap it. It avoids having to explicitly specify a column width.
%TABLE{ columnwidths="20,400,33%" }%
Suggest also to accept the value "nowrap" for the width of a column:
%TABLE{ columnwidths="20,nowrap,33%" }%