优化占位高度及容器默认内边距 (#8204)

* fix: 修复选中组件点击添加新组件方式报错

* chore: 优化容器插件占位高度及默认内边距

* chore: 删掉一个多余的占位颜色

packages/amis-editor-core/scss/editor.scss

@@ -1227,7 +1227,6 @@
   &.layout-content {
     height: 100%;
     min-height: 88px;
-    background: #f7f7f8;
   }
 
   &.fill-placeholder {
@@ -1248,7 +1247,7 @@
 
 [data-region] {
   position: relative;
-  min-height: 10px;
+  min-height: 34px;
 
   &:empty {
     min-width: 20px;
@@ -1336,6 +1335,10 @@
   }
 }
 
+[data-renderer='container'] {
+  min-height: 0;
+}
+
 // 移动端有问题，先注释了
 
 // 优化画布区页面展示效果

packages/amis-editor-core/src/manager.ts

@@ -977,7 +977,7 @@ export class EditorManager {
       let beforeId = -1;
       parent.some((item: any, index: number) => {
         let result = false;
-        if (item.$$id === curActiveId) {
+        if (item?.$$id === curActiveId) {
           beforeId = index;
           result = true;
         }

packages/amis-editor-core/src/store/editor.ts

@@ -1154,7 +1154,7 @@ export const MainStore = types
         if (event.context.beforeId) {
           const idx = findIndex(
             arr,
-            (item: any) => item.$$id === event.context.beforeId
+            (item: any) => item?.$$id === event.context.beforeId
           );
           ~idx ? arr.splice(idx, 0, child) : arr.push(child);
         } else {

packages/amis-editor/src/plugin/Container.tsx

@@ -34,6 +34,7 @@ export class ContainerPlugin extends LayoutBasePlugin {
       position: 'static',
       display: 'block'
     },
+    size: 'none',
     wrapperBody: false
   };
   previewSchema = {