Currently there is no inbuilt option to prevent input overflow, option might be added in upcoming versions.
Meanwhile you may use this to prevent input overflow.
$.paramquery.cEditor.prototype.fixWidth = function( ui ){
var that = this.that,
$td = ui.$td, td = $td[0],
width = td.offsetWidth,
$grid = that.widget(),
$editor = ui.$editor;
$editor.css("width", width+"px");
this.position($editor, $grid, $td);
}