code: public boolean onBack()
      {
          BasePanel parent = this.getParentScreen();
          if (parent == null)
              return false;
          parent.popHistory(1, false);        // Pop command for this screen
          String strLastCommand = parent.popHistory(1, false);
          if (strLastCommand != null)		// I don't back up into the browser history if the user hit the java back button.
          {	// If that wasn't the first screen, redo pop and update the browser this time
          	parent.pushHistory(strLastCommand, false);
          	strLastCommand = parent.popHistory(1, true);
          }
          if ((strLastCommand == null) || (strLastCommand.length() == 0))
          {
              if (parent.getParentScreen() != null)
                  if (!(parent.getParentScreen() instanceof FrameScreen))
                      return parent.onBack();
              // ++Add++ No more to pop, display home screen (if push-down gets messed up)
              parent.pushHistory(this.getScreenURL(), false);    // This is the first screen in the stack
          }
          else
              this.handleCommand(strLastCommand, this, ScreenConstants.USE_SAME_WINDOW | ScreenConstants.DONT_PUSH_TO_BROWSER);     // Process the last command
          return true;    // Handled
      }
docs: Process the "Back" toolbar command.
  @return true if successful.