code: public void setHideFixedToolbarsIfContentAreaPercentBelow(double value) {
          double oldVal = hideFixedToolbarsIfContentAreaPercentBelow;
          hideFixedToolbarsIfContentAreaPercentBelow = value;
          if (oldVal != hideFixedToolbarsIfContentAreaPercentBelow
                  && content != null && content.isAttached()) {
              processFixedToolbars();
              centerContent();
              initWindowResize();
          }
      }
docs: Fixed Header and Footer will be hidden if content area height percent is below
  than specified percent of window height (default is 50%).
  <br> Useful in cases with activated virtual keyboard, especially on Android.