col-num not working

[V-yw]

• Browser Google Chrome 118.0.5993.117
• Vue Version Vue.js v2.7.14
• vue-grid-layout Version: vue-grid-layout - 2.4.0

When I set colNum to 12 columns, it has no effect. I opened Google's vue plug-in and checked that clos is automatic. Below is an example of part of my code.But it works if I adjust row-height

<grid-layout ref="gridlayout" :layout.sync="layout" :col-num="12" {# :cols="12"#} :row-height="30" :is-draggable="true" :is-resizable="true" :is-mirrored="false" :vertical-compact="true" :margin="[10, 10]" :responsive="true" :use-css-transforms="true" class="vue-grid-layout" >