What is the purpose of the 中 in 在新标签页中打开? So, I recently started using my android phone in simplified Chinese mode, to help myself internalize Chinese characters. In my browser window, when I press down on a URL, the "在新标签页中打开" button allows me to open a new tab. 

So I tried to translate the sentence literally by dictionary definitions, and I came up with this:


  在新标签页中打开: In new tab page, middle open.


So why is the 中 (middle) necessary? Without it, the sentence makes sense to me. Could it be functioning as a preposition? If so, then why would I need both 中 and 在 in this sentence?
在 and 中 are serving two different functions here.

The preposition 在 at the start of the sentence indicates where something happens. Meanwhile, the 中 here is technically a noun meaning "the inside", not "middle". It signifies that the link is opened on a new tab page, i.e. *the inside of a tab page".

Taken as a whole, then, the Chinese sentence is actually saying: Open link (打开) at [the position of] (在) a new tab page's (新标签页) insides (中) .

Without the 中 the sentence would still make enough sense to be understood, but it would sound weird. Generally speaking, when the target of 在 is not a location, it is standard to add 中 or 裡 etc. For example, 住在美國 and 住在公寓裡 .