message: fix member list height
diff: .jsxc-memberlist {
  background-color: $window_bar_bg;
  - height: 0;
  + max-height: 0;
  overflow: auto;
  position: absolute;
  top: 0;
  - transition: height 400ms;
  + transition: max-height 400ms;
  width: 100%;
  z-index: 100;
  @extend %scrollbar;
  &.jsxc-expand {
  - height: 120px;
  + max-height: 120px;
  }
  ul {
  