diff --git a/src/App.js b/src/App.js
index 85058a5..d2863be 100644
--- a/src/App.js
+++ b/src/App.js
@@ -7,6 +7,8 @@ import {TokenCtx} from './UserAction';
 import {load_config,bgimg_style} from './Config';
 import {listen_darkmode} from './infrastructure/functions';
 
+const MAX_SIDEBAR_STACK_SIZE=10;
+
 function DeprecatedAlert(props) {
     return null;
 }
@@ -47,32 +49,25 @@ class App extends Component {
     }
 
     show_sidebar(title,content,mode='push') {
-        if(mode==='push') {
-            this.setState((prevState)=>({
-                sidebar_stack: prevState.sidebar_stack.concat([[title,content]]),
-            }));
-        } else if(mode==='pop') {
-            this.setState((prevState)=>{
-                let ns=prevState.sidebar_stack.slice();
+        this.setState((prevState)=>{
+            let ns=prevState.sidebar_stack.slice();
+            if(mode==='push') {
+                if(ns.length>MAX_SIDEBAR_STACK_SIZE)
+                    ns.splice(1,1);
+                ns=ns.concat([[title,content]]);
+            } else if(mode==='pop') {
                 ns.pop();
-                return {
-                    sidebar_stack: ns,
-                };
-            });
-        } else if(mode==='replace') {
-            this.setState((prevState)=>{
-                let ns=prevState.sidebar_stack.slice();
+            } else if(mode==='replace') {
                 ns.pop();
-                return {
-                    sidebar_stack: ns.concat([[title,content]]),
-                };
-            });
-        } else if(mode==='clear') {
-            this.setState({
-                sidebar_stack: [[null,null]],
-            });
-        } else
-            throw new Error('bad show_sidebar mode');
+                ns=ns.concat([[title,content]]);
+            } else if(mode==='clear') {
+                ns=[[null,null]];
+            } else
+                throw new Error('bad show_sidebar mode');
+            return {
+                sidebar_stack: ns,
+            };
+        });
     }
 
     set_mode(mode,search_text) {
diff --git a/src/Flows.js b/src/Flows.js
index a0ffbc3..8d39d2f 100644
--- a/src/Flows.js
+++ b/src/Flows.js
@@ -21,7 +21,7 @@ window.LATEST_POST_ID=parseInt(localStorage['_LATEST_POST_ID'],10)||0;
 
 const DZ_NAME='洞主';
 
-function load_single_meta(show_sidebar,token,parents) {
+function load_single_meta(show_sidebar,token) {
     return (pid)=>{
         let color_picker=new ColorPicker();
         let title_elem='树洞 #'+pid;
@@ -47,7 +47,7 @@ function load_single_meta(show_sidebar,token,parents) {
                     <FlowSidebar key={+new Date()}
                         info={single.data} replies={replies.data} attention={replies.attention}
                         token={token} show_sidebar={show_sidebar} color_picker={color_picker}
-                        deletion_detect={localStorage['DELETION_DETECT']==='on'} parents={parents}
+                        deletion_detect={localStorage['DELETION_DETECT']==='on'}
                     />,
                     'replace'
                 )
@@ -57,7 +57,7 @@ function load_single_meta(show_sidebar,token,parents) {
                 show_sidebar(
                     title_elem,
                     <div className="box box-tip">
-                        <p><a onClick={()=>load_single_meta(show_sidebar,token,parents)(pid)}>重新加载</a></p>
+                        <p><a onClick={()=>load_single_meta(show_sidebar,token)(pid)}>重新加载</a></p>
                         <p>{''+e}</p>
                     </div>,
                     'replace'
@@ -335,7 +335,7 @@ class FlowSidebar extends PureComponent {
         if(this.state.loading_status==='loading')
             return (<p className="box box-tip">加载中……</p>);
 
-        let show_pid=load_single_meta(this.props.show_sidebar,this.props.token,this.props.parents.concat([this.state.info.pid]));
+        let show_pid=load_single_meta(this.props.show_sidebar,this.props.token);
 
         let replies_to_show=this.state.filter_name ? this.state.replies.filter((r)=>r.name===this.state.filter_name) : this.state.replies.slice();
         if(this.state.rev) replies_to_show.reverse();
@@ -496,7 +496,7 @@ class FlowItemRow extends PureComponent {
             <FlowSidebar key={+new Date()}
                 info={this.state.info} replies={this.state.replies} attention={this.state.attention} sync_state={this.setState.bind(this)}
                 token={this.props.token} show_sidebar={this.props.show_sidebar} color_picker={this.color_picker}
-                deletion_detect={this.props.deletion_detect} parents={[]}
+                deletion_detect={this.props.deletion_detect}
             />
         );
     }