make CSS work on FF

src/skins/vector/css/matrix-react-sdk/views/rooms/MemberList.css

@@ -51,14 +51,14 @@ limitations under the License.
 }
 
 .mx_MemberList .mx_SearchableEntityList_expanded {
-    flex: 1 1 0;
-    -webkit-flex: 1 1 0;
+    flex: 1 1 100%;
+    -webkit-flex: 1 1 100%;
 }
 
 .mx_MemberList_joined {
     order: 2;
-    flex: 1 1 auto;
-    -webkit-flex: 1 1 auto;
+    flex: 1 1 50%;
+    -webkit-flex: 1 1 50%;
 
     overflow-y: auto;
 }
@@ -76,7 +76,9 @@ limitations under the License.
     order: 4;
     flex: 0 0 72px;
     -webkit-flex: 0 0 72px;
+}
 
+.mx_MemberList_bottomRule {
     border-top: 2px solid #e1dddd;
     margin-right: 15px;
 }

src/skins/vector/css/matrix-react-sdk/views/rooms/SearchableEntityList.css

@@ -15,9 +15,6 @@ limitations under the License.
 */
 
 .mx_SearchableEntityList {
-    flex: 1;
-    -webkit-flex: 1;
-
     display: flex;
     display: -webkit-flex;
 
@@ -66,7 +63,7 @@ limitations under the License.
 
 .mx_SearchableEntityList_hrWrapper {
     width: 100%;
-    flex: 0px;
+    flex: 0;
     -webkit-flex: 0;    
 }