private void registerCustomKeyboardActions() {
    int mask = ClientSystemInfo.isMac() ? InputEvent.META_DOWN_MASK : InputEvent.ALT_DOWN_MASK;

    registerKeyboardAction(__ -> focusEditor(), KeyStroke.getKeyStroke(KeyEvent.VK_T, mask));

    registerKeyboardAction(__ -> focusTree(), KeyStroke.getKeyStroke(KeyEvent.VK_S, mask));

    registerKeyboardAction(__ -> myBlockTree.focusTree(), KeyStroke.getKeyStroke(KeyEvent.VK_K, mask));

    registerKeyboardAction(__ -> focusRefs(), KeyStroke.getKeyStroke(KeyEvent.VK_R, mask));

    registerKeyboardAction(__ -> {
      if (myRefs.isFocusOwner()) {
        myBlockTree.focusTree();
      }
      else if (myPsiTree.isFocusOwner()) {
        focusRefs();
      }
      else if (myBlockTree.isFocusOwner()) {
        focusTree();
      }
    }, KeyStroke.getKeyStroke(KeyEvent.VK_TAB, 0));
  }
private void registerCustomKeyboardActions()