(Their offices were separated only by a glass door, apparently never closed).

他们的办公室只隔着一块玻璃门，显然从不关闭。

youdao

In the teens, the door is made of glass, frail yet transparent. Though closed, people inside could look outside clearly, and vice versa.

十几岁的心扉是玻璃的，脆弱而且透明，虽然关着，但是里面的人不断向外张望，外面的人也能窥视门内。

youdao

Sliding glass door can be kept open to encourage collaboration, or closed for conference calls or meetings.

WSJ: Offices to Make You Work Harder