This is a known bug introduced in jupyterlab-git 0.22.2. The comments in the GitHub issue mention that refreshing browser may help but I have not tried it. This issue was fixed in the new version for JupyterLab 3.0 (currently in beta) - you can install it with:
pip install jupyterlab==3
pip install --pre jupyterlab-git==0.30.0b1
If you cannot yet update to JupyterLab 3.x, you can downgrade to 0.22.1 which is not affected:
pip install jupyterlab-git==0.22.1
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…