diff --git a/res/css/structures/_LeftPanel.scss b/res/css/structures/_LeftPanel.scss
index ca4a5ea6f3..fc1622aa4d 100644
--- a/res/css/structures/_LeftPanel.scss
+++ b/res/css/structures/_LeftPanel.scss
@@ -48,10 +48,10 @@ limitations under the License.
 .mx_LeftPanel {
     background-color: $secondary-accent-color;
     flex: 1;
-    position: relative;
     overflow-x: hidden;
     display: flex;
     flex-direction: column;
+    min-height: 0;
 }
 
 .mx_LeftPanel .mx_AppTile_mini {
diff --git a/res/css/structures/_MatrixChat.scss b/res/css/structures/_MatrixChat.scss
index 4f817eef44..a6027f246f 100644
--- a/res/css/structures/_MatrixChat.scss
+++ b/res/css/structures/_MatrixChat.scss
@@ -54,6 +54,7 @@ limitations under the License.
     order: 2;
 
     flex: 1;
+    min-height: 0;
 }
 
 .mx_MatrixChat_syncError {
diff --git a/res/css/views/rooms/_RoomList.scss b/res/css/views/rooms/_RoomList.scss
index 29f5fcdadf..d38c124e32 100644
--- a/res/css/views/rooms/_RoomList.scss
+++ b/res/css/views/rooms/_RoomList.scss
@@ -21,6 +21,7 @@ limitations under the License.
     /* use flexbox to layout sublists */
     display: flex;
     flex-direction: column;
+    min-height: 0;
 }
 
 /* hide resize handles next to collapsed / empty sublists */
diff --git a/src/components/structures/RoomSubList.js b/src/components/structures/RoomSubList.js
index 0c166a7928..490a84bb7f 100644
--- a/src/components/structures/RoomSubList.js
+++ b/src/components/structures/RoomSubList.js
@@ -344,7 +344,7 @@ const RoomSubList = React.createClass({
                 "mx_RoomSubList_nonEmpty": len && !this.state.hidden,
             });
             if (this.state.hidden) {
-                return <div className={subListClasses}>
+                return <div className={subListClasses} style={{flexBasis: "unset", flexGrow: "unset"}}>
                     {this._getHeaderJsx()}
                 </div>;
             } else {
diff --git a/src/resizer/sizer.js b/src/resizer/sizer.js
index 4ae35e020a..303214854b 100644
--- a/src/resizer/sizer.js
+++ b/src/resizer/sizer.js
@@ -99,6 +99,7 @@ class Sizer {
 
 class FlexSizer extends Sizer {
     setItemSize(item, size) {
+        item.style.flexGrow = `0`;
         item.style.flexBasis = `${Math.round(size)}px`;
     }
 }