1、解决extjs 3 chrome上grid  cm错位的问题，这个是Extjs 的一个bug

问题如图片下

2.解决方法官方的

http://www.sencha.com/forum/archive/index.php/t-198124.html?s=782e3297b3794980e855431bf90e6172

Ext.grid.ColumnModel.override({  
        getTotalWidth: function(includeHidden) {  
            var off = 0;  
            if (Ext.isChrome){  
                off = 2;  
            };  
            if (!this.totalWidth) {  
                this.totalWidth = 0;  
                for (var i = 0, len = this.config.length; i < len; i++) {  
                    if (includeHidden || !this.isHidden(i)) {  
                        this.totalWidth += this.getColumnWidth(i)+off;  
                    };  
                };  
            };  
            return this.totalWidth;  
   }  
});