code: public void showPanel() {
          if (mFirstLayout) {
              mSlideState = SlideState.COLLAPSED;
          } else {
              if (mSlideableView == null || mSlideState != SlideState.HIDDEN) return;
              mSlideableView.setVisibility(View.VISIBLE);
              requestLayout();
              smoothSlideTo(0, 0);
          }
      }
docs: Shows the panel from the hidden state