private void setSplitterDiffPreview() {
      boolean hasSplitterPreview = !isCommitToolWindowShown(myProject);

      //noinspection DoubleNegation
      boolean needUpdatePreview = hasSplitterPreview != (mySplitterDiffPreview != null);
      if (!needUpdatePreview) return;

      if (hasSplitterPreview) {
        mySplitterDiffPreview = new ShelveSplitterDiffPreview();
        DiffPreview.setPreviewVisible(mySplitterDiffPreview, myVcsConfiguration.SHELVE_DETAILS_PREVIEW_SHOWN);
      }
      else {
        Disposer.dispose(mySplitterDiffPreview);
        mySplitterDiffPreview = null;
      }
    }
private void setSplitterDiffPreview()